diff --git a/EDMarketConnector.py b/EDMarketConnector.py
index 37e34ea5..95f7aac7 100755
--- a/EDMarketConnector.py
+++ b/EDMarketConnector.py
@@ -1,7 +1,6 @@
 #!/usr/bin/python
 # -*- coding: utf-8 -*-
 
-import sys
 from sys import platform
 import json
 from os import mkdir
@@ -17,6 +16,7 @@ import tkFont
 if __debug__:
     from traceback import print_exc
 
+import l10n
 import companion
 import bpc
 import td
@@ -27,8 +27,9 @@ import flightlog
 import prefs
 from config import appname, applongname, config
 
+l10n.Translations().install()
 
-shipyard_retry = 5	# retry pause for shipyard data [s]
+SHIPYARD_RETRY = 5	# retry pause for shipyard data [s]
 
 
 class AppWindow:
@@ -67,14 +68,14 @@ class AppWindow:
         frame.columnconfigure(1, weight=1)
         frame.rowconfigure(4, weight=1)
 
-        ttk.Label(frame, text="Cmdr:").grid(row=0, column=0, sticky=tk.W)
-        ttk.Label(frame, text="System:").grid(row=1, column=0, sticky=tk.W)
-        ttk.Label(frame, text="Station:").grid(row=2, column=0, sticky=tk.W)
+        ttk.Label(frame, text=_('Cmdr:')).grid(row=0, column=0, sticky=tk.W)	# Main window
+        ttk.Label(frame, text=_('System:')).grid(row=1, column=0, sticky=tk.W)	# Main window
+        ttk.Label(frame, text=_('Station:')).grid(row=2, column=0, sticky=tk.W)	# Main window
 
         self.cmdr = ttk.Label(frame, width=-20)
         self.system = ttk.Label(frame, width=-20)
         self.station = ttk.Label(frame, width=-20)
-        self.button = ttk.Button(frame, text='Update', command=self.getandsend, default=tk.ACTIVE, state=tk.DISABLED)
+        self.button = ttk.Button(frame, text=_('Update'), command=self.getandsend, default=tk.ACTIVE, state=tk.DISABLED)	# Update button in main window
         self.status = ttk.Label(frame, width=-25)
         self.w.bind('<Return>', self.getandsend)
         self.w.bind('<KP_Enter>', self.getandsend)
@@ -93,12 +94,13 @@ class AppWindow:
             from Foundation import NSBundle
             # https://www.tcl.tk/man/tcl/TkCmd/menu.htm
             apple_menu = tk.Menu(menubar, name='apple')
-            apple_menu.add_command(label="About %s" % applongname, command=lambda:self.w.call('tk::mac::standardAboutPanel'))
-            apple_menu.add_command(label="Check for Update", command=lambda:self.updater.checkForUpdates())
+            apple_menu.add_command(label=_("About {APP}").format(APP=applongname), command=lambda:self.w.call('tk::mac::standardAboutPanel'))	# App menu entry on OSX
+            apple_menu.add_command(label=_("Check for Updates..."), command=lambda:self.updater.checkForUpdates())
             menubar.add_cascade(menu=apple_menu)
             window_menu = tk.Menu(menubar, name='window')
             menubar.add_cascade(menu=window_menu)
             # https://www.tcl.tk/man/tcl/TkCmd/tk_mac.htm
+            self.w.call('set', 'tk::mac::useCompatibilityMetrics', '0')
             self.w.createcommand('tkAboutDialog', lambda:self.w.call('tk::mac::standardAboutPanel'))
             self.w.createcommand("::tk::mac::Quit", self.onexit)
             self.w.createcommand("::tk::mac::ShowPreferences", lambda:prefs.PreferencesDialog(self.w, self.login))
@@ -106,11 +108,11 @@ class AppWindow:
             self.w.protocol("WM_DELETE_WINDOW", self.w.withdraw)	# close button shouldn't quit app
         else:
             file_menu = tk.Menu(menubar, tearoff=tk.FALSE)
-            file_menu.add_command(label="Check for Update", command=lambda:self.updater.checkForUpdates())
-            file_menu.add_command(label="Settings", command=lambda:prefs.PreferencesDialog(self.w, self.login))
+            file_menu.add_command(label=_("Check for Updates..."), command=lambda:self.updater.checkForUpdates())
+            file_menu.add_command(label=_("Settings"), command=lambda:prefs.PreferencesDialog(self.w, self.login))	# Menu item
             file_menu.add_separator()
-            file_menu.add_command(label="Exit", command=self.onexit)
-            menubar.add_cascade(label="File", menu=file_menu)
+            file_menu.add_command(label=_("Exit"), command=self.onexit)	# Menu item
+            menubar.add_cascade(label=_("File"), menu=file_menu)	# Top-level menu on Windows
             self.w.protocol("WM_DELETE_WINDOW", self.onexit)
         if platform == 'linux2':
             # Fix up menu to use same styling as everything else
@@ -148,7 +150,7 @@ class AppWindow:
 
     # call after credentials have changed
     def login(self):
-        self.status['text'] = 'Logging in...'
+        self.status['text'] = _('Logging in...')
         self.button['state'] = tk.DISABLED
         self.w.update_idletasks()
         try:
@@ -188,7 +190,7 @@ class AppWindow:
         if not retrying:
             if time() < self.holdofftime: return	# Was invoked by Return key while in cooldown
             self.cmdr['text'] = self.system['text'] = self.station['text'] = ''
-            self.status['text'] = 'Fetching station data...'
+            self.status['text'] = _('Fetching station data...')
             self.button['state'] = tk.DISABLED
             self.w.update_idletasks()
 
@@ -206,15 +208,15 @@ class AppWindow:
 
             # Validation
             if not data.get('commander') or not data['commander'].get('name','').strip():
-                self.status['text'] = "Who are you?!"		# Shouldn't happen
+                self.status['text'] = _("Who are you?!")		# Shouldn't happen
             elif not data.get('lastSystem') or not data['lastSystem'].get('name','').strip() or not data.get('lastStarport') or not data['lastStarport'].get('name','').strip():
-                self.status['text'] = "Where are you?!"		# Shouldn't happen
+                self.status['text'] = _("Where are you?!")		# Shouldn't happen
             elif not data.get('ship') or not data['ship'].get('modules') or not data['ship'].get('name','').strip():
-                self.status['text'] = "What are you flying?!"	# Shouldn't happen
+                self.status['text'] = _("What are you flying?!")	# Shouldn't happen
 
             elif (config.getint('output') & config.OUT_EDDN) and data['commander'].get('docked') and not data['lastStarport'].get('ships') and not retrying:
                 # API is flakey about shipyard info - retry if missing (<1s is usually sufficient - 5s for margin).
-                self.w.after(shipyard_retry * 1000, lambda:self.getandsend(retrying=True))
+                self.w.after(SHIPYARD_RETRY * 1000, lambda:self.getandsend(retrying=True))
 
                 # Stuff we can do while waiting for retry
                 if config.getint('output') & config.OUT_LOG:
@@ -243,10 +245,10 @@ class AppWindow:
 
                 if not (config.getint('output') & (config.OUT_CSV|config.OUT_TD|config.OUT_BPC|config.OUT_EDDN)):
                     # no further output requested
-                    self.status['text'] = strftime('Last updated at %H:%M:%S', localtime(querytime))
+                    self.status['text'] = strftime(_('Last updated at {HH}:{MM}:{SS}').format(HH='%H', MM='%M', SS='%S').encode('utf-8'), localtime(querytime)).decode('utf-8')
 
                 elif not data['commander'].get('docked'):
-                    self.status['text'] = "You're not docked at a station!"
+                    self.status['text'] = _("You're not docked at a station!")
                 else:
                     if data['lastStarport'].get('commodities'):
                         # Fixup anomalies in the commodity data
@@ -261,16 +263,16 @@ class AppWindow:
 
                     if config.getint('output') & config.OUT_EDDN:
                         if data['lastStarport'].get('commodities') or data['lastStarport'].get('modules') or data['lastStarport'].get('ships'):
-                            self.status['text'] = 'Sending data to EDDN...'
+                            self.status['text'] = _('Sending data to EDDN...')
                             self.w.update_idletasks()
                             eddn.export(data)
-                            self.status['text'] = strftime('Last updated at %H:%M:%S', localtime(querytime))
+                            self.status['text'] = strftime(_('Last updated at {HH}:{MM}:{SS}').format(HH='%H', MM='%M', SS='%S').encode('utf-8'), localtime(querytime)).decode('utf-8')
                         else:
-                            self.status['text'] = "Station doesn't have anything!"
+                            self.status['text'] = _("Station doesn't have anything!")
                     elif not data['lastStarport'].get('commodities'):
-                        self.status['text'] = "Station doesn't have a market!"
+                        self.status['text'] = _("Station doesn't have a market!")
                     else:
-                        self.status['text'] = strftime('Last updated at %H:%M:%S', localtime(querytime))
+                        self.status['text'] = strftime(_('Last updated at {HH}:{MM}:{SS}').format(HH='%H', MM='%M', SS='%S').encode('utf-8'), localtime(querytime)).decode('utf-8')
 
         except companion.VerificationRequired:
             return prefs.AuthenticationDialog(self.w, self.verify)
@@ -281,11 +283,11 @@ class AppWindow:
 
         except requests.exceptions.ConnectionError as e:
             if __debug__: print_exc()
-            self.status['text'] = "Error: Can't connect to EDDN"
+            self.status['text'] = _("Error: Can't connect to EDDN")
 
         except requests.exceptions.Timeout as e:
             if __debug__: print_exc()
-            self.status['text'] = "Error: Connection to EDDN timed out"
+            self.status['text'] = _("Error: Connection to EDDN timed out")
 
         except Exception as e:
             if __debug__: print_exc()
@@ -295,10 +297,10 @@ class AppWindow:
 
     def cooldown(self):
         if time() < self.holdofftime:
-            self.button['text'] = 'cool down %ds' % (self.holdofftime - time())
+            self.button['text'] = _('cooldown {SS}s').format(SS = int(self.holdofftime - time()))	# Update button in main window
             self.w.after(1000, self.cooldown)
         else:
-            self.button['text'] = 'Update'
+            self.button['text'] = _('Update')	# Update button in main window
             self.button['state'] = tk.NORMAL
 
     def onexit(self, event=None):
diff --git a/L10n/en.template b/L10n/en.template
new file mode 100644
index 00000000..4561c53c
--- /dev/null
+++ b/L10n/en.template
@@ -0,0 +1,150 @@
+/* Use same text as E:D Launcher's verification dialog. [prefs.py:208] */
+"A verification code has now been sent to the{CR}email address associated with your Elite account." = "A verification code has now been sent to the{CR}email address associated with your Elite account.";
+
+/* App menu entry on OSX. [EDMarketConnector.py:97] */
+"About {APP}" = "About {APP}";
+
+/* Folder selection button on Windows. [prefs.py:101] */
+"Browse..." = "Browse...";
+
+/* Folder selection button on OSX. [prefs.py:100] */
+"Change..." = "Change...";
+
+/* [EDMarketConnector.py:98] */
+"Check for Updates..." = "Check for Updates...";
+
+/* Privacy setting. [prefs.py:114] */
+"Cmdr name" = "Cmdr name";
+
+/* Main window. [EDMarketConnector.py:71] */
+"Cmdr:" = "Cmdr:";
+
+/* Update button in main window. [EDMarketConnector.py:300] */
+"cooldown {SS}s" = "cooldown {SS}s";
+
+/* Section heading in settings. [prefs.py:58] */
+"Credentials" = "Credentials";
+
+/* [EDMarketConnector.py:286] */
+"Error: Can't connect to EDDN" = "Error: Can't connect to EDDN";
+
+/* [EDMarketConnector.py:290] */
+"Error: Connection to EDDN timed out" = "Error: Connection to EDDN timed out";
+
+/* [companion.py:107] */
+"Error: Invalid Credentials" = "Error: Invalid Credentials";
+
+/* [companion.py:103] */
+"Error: Server is down" = "Error: Server is down";
+
+/* Menu item. [EDMarketConnector.py:114] */
+"Exit" = "Exit";
+
+/* [EDMarketConnector.py:193] */
+"Fetching station data..." = "Fetching station data...";
+
+/* Top-level menu on Windows. [EDMarketConnector.py:115] */
+"File" = "File";
+
+/* Output folder prompt on Windows. [prefs.py:99] */
+"File location:" = "File location:";
+
+/* [prefs.py:96] */
+"Flight log" = "Flight log";
+
+/* Shouldn't happen. [companion.py:176] */
+"General error" = "General error";
+
+/* [prefs.py:113] */
+"How do you want to be identified in the saved data" = "How do you want to be identified in the saved data";
+
+/* [EDMarketConnector.py:248] */
+"Last updated at {HH}:{MM}:{SS}" = "Last updated at {HH}:{MM}:{SS}";
+
+/* [EDMarketConnector.py:153] */
+"Logging in..." = "Logging in...";
+
+/* [prefs.py:90] */
+"Market data in CSV format" = "Market data in CSV format";
+
+/* [prefs.py:86] */
+"Market data in Slopey's BPC format" = "Market data in Slopey's BPC format";
+
+/* [prefs.py:88] */
+"Market data in Trade Dangerous format" = "Market data in Trade Dangerous format";
+
+/* [prefs.py:124] */
+"OK" = "OK";
+
+/* Section heading in settings. [prefs.py:77] */
+"Output" = "Output";
+
+/* Use same text as E:D Launcher's login dialog. [prefs.py:64] */
+"Password" = "Password";
+
+/* [prefs.py:82] */
+"Please choose what data to save" = "Please choose what data to save";
+
+/* Use same text as E:D Launcher's verification dialog. [prefs.py:211] */
+"Please enter the code into the box below." = "Please enter the code into the box below.";
+
+/* Use same text as E:D Launcher's login dialog. [prefs.py:62] */
+"Please log in with your Elite: Dangerous account details" = "Please log in with your Elite: Dangerous account details";
+
+/* [prefs.py:37] */
+"Preferences" = "Preferences";
+
+/* Section heading in settings. [prefs.py:108] */
+"Privacy" = "Privacy";
+
+/* Privacy setting. [prefs.py:115] */
+"Pseudo-anonymized ID" = "Pseudo-anonymized ID";
+
+/* [prefs.py:84] */
+"Send station data to the Elite Dangerous Data Network" = "Send station data to the Elite Dangerous Data Network";
+
+/* [EDMarketConnector.py:266] */
+"Sending data to EDDN..." = "Sending data to EDDN...";
+
+/* Menu item. [EDMarketConnector.py:112] */
+"Settings" = "Settings";
+
+/* [prefs.py:94] */
+"Ship loadout in Coriolis format" = "Ship loadout in Coriolis format";
+
+/* [prefs.py:92] */
+"Ship loadout in E:D Shipyard format" = "Ship loadout in E:D Shipyard format";
+
+/* [EDMarketConnector.py:273] */
+"Station doesn't have a market!" = "Station doesn't have a market!";
+
+/* [EDMarketConnector.py:271] */
+"Station doesn't have anything!" = "Station doesn't have anything!";
+
+/* Main window. [EDMarketConnector.py:73] */
+"Station:" = "Station:";
+
+/* Main window. [EDMarketConnector.py:72] */
+"System:" = "System:";
+
+/* Update button in main window. [EDMarketConnector.py:78] */
+"Update" = "Update";
+
+/* Use same text as E:D Launcher's login dialog. [prefs.py:63] */
+"Username (Email)" = "Username (Email)";
+
+/* Shouldn't happen. [EDMarketConnector.py:215] */
+"What are you flying?!" = "What are you flying?!";
+
+/* Shouldn't happen. [EDMarketConnector.py:213] */
+"Where are you?!" = "Where are you?!";
+
+/* Output folder prompt on OSX. [prefs.py:98] */
+"Where:" = "Where:";
+
+/* Shouldn't happen. [EDMarketConnector.py:211] */
+"Who are you?!" = "Who are you?!";
+
+/* [EDMarketConnector.py:251] */
+"You're not docked at a station!" = "You're not docked at a station!";
+
diff --git a/companion.py b/companion.py
index f546a2db..59debd41 100644
--- a/companion.py
+++ b/companion.py
@@ -100,15 +100,14 @@ def listify(thing):
 
 class ServerError(Exception):
     def __str__(self):
-        return 'Error: Server is down'
+        return _('Error: Server is down')
 
 class CredentialsError(Exception):
     def __str__(self):
-        return 'Error: Invalid Credentials'
+        return _('Error: Invalid Credentials')
 
 class VerificationRequired(Exception):
-    def __str__(self):
-        return 'Authentication required'
+    pass
 
 # Server companion.orerve.net uses a session cookie ("CompanionApp") to tie together login, verification
 # and query. So route all requests through a single Session object which holds this state.
@@ -174,7 +173,7 @@ class Session:
 
     def query(self):
         if self.state == Session.STATE_NONE:
-            raise Exception('General error')	# Shouldn't happen
+            raise Exception(_('General error'))	# Shouldn't happen
         elif self.state == Session.STATE_INIT:
             self.login()
         elif self.state == Session.STATE_AUTH:
diff --git a/l10n.py b/l10n.py
new file mode 100755
index 00000000..0c6ea08e
--- /dev/null
+++ b/l10n.py
@@ -0,0 +1,152 @@
+#!/usr/bin/python
+#
+# Localization with gettext is a pain on non-Unix systems. Use OSX-style strings files instead.
+#
+
+import codecs
+import os
+from os.path import dirname, isfile, join, normpath
+import re
+import sys
+from sys import platform
+import __builtin__
+
+
+class Translations:
+
+    FALLBACK = 'en'	# strings in this code are in English
+
+    def __init__(self):
+        self.translations = {}
+
+    def install(self):
+        path = join(self.respath(), 'L10n')
+        available = self.available()
+        available.add(Translations.FALLBACK)
+
+        for preferred in self.preferred():
+            if preferred in available:
+                lang = preferred
+                break
+        else:
+            for preferred in self.preferred():
+                preferred = preferred.split('-',1)[0]	# just base language
+                if preferred in available:
+                    lang = preferred
+                    break
+            else:
+                lang = Translations.FALLBACK
+
+        if lang not in self.available():
+            __builtin__.__dict__['_'] = lambda x: x
+        else:
+            regexp = re.compile(r'\s*"([^"]+)"\s*=\s*"([^"]+)"\s*;\s*$')
+            comment= re.compile(r'\s*/\*.*\*/\s*$')
+            with self.file(lang) as h:
+                for line in h:
+                    if line.strip():
+                        match = regexp.match(line)
+                        if match:
+                            self.translations[match.group(1)] = match.group(2)
+                        elif not comment.match(line):
+                            assert match, 'Bad translation: %s' % line
+            __builtin__.__dict__['_'] = self.translate
+
+    if __debug__:
+        def translate(self, x):
+            if x in self.translations:
+                return self.translations[x]
+            else:
+                print 'Missing translation: "%s"' % x
+    else:
+        def translate(self, x):
+            return self.translations.get(x, x)
+
+    # Returns list of available language codes
+    def available(self):
+        path = self.respath()
+        if getattr(sys, 'frozen', False) and platform=='darwin':
+            available = set([x[:-len('.lproj')] for x in os.listdir(path) if x.endswith('.lproj') and isfile(join(x, 'Localizable.strings'))])
+        else:
+            available = set([x[:-len('.strings')] for x in os.listdir(path) if x.endswith('.strings')])
+        return available
+
+    # Returns list of preferred language codes in lowercase RFC4646 format.
+    # Typically "lang[-script][-region]" where lang is a 2 alpha ISO 639-1 or 3 alpha ISO 639-2 code,
+    # script is a 4 alpha ISO 15924 code and region is a 2 alpha ISO 3166 code
+    def preferred(self):
+
+        if platform=='darwin':
+            from Foundation import NSLocale
+            return [x.lower() for x in NSLocale.preferredLanguages()] or None
+
+        elif platform=='win32':
+
+            def wszarray_to_list(array):
+                offset = 0
+                while offset < len(array):
+                    sz = ctypes.wstring_at(ctypes.addressof(array) + offset*2)
+                    if sz:
+                        yield sz
+                        offset += len(sz)+1
+                    else:
+                        break
+
+            # https://msdn.microsoft.com/en-us/library/windows/desktop/dd318124%28v=vs.85%29.aspx
+            import ctypes
+            MUI_LANGUAGE_ID = 4
+            MUI_LANGUAGE_NAME = 8
+            GetUserPreferredUILanguages = ctypes.windll.kernel32.GetUserPreferredUILanguages
+
+            num = ctypes.c_ulong()
+            size = ctypes.c_ulong(0)
+            if (GetUserPreferredUILanguages(MUI_LANGUAGE_NAME, ctypes.byref(num), None, ctypes.byref(size)) and size.value):
+                buf = ctypes.create_unicode_buffer(size.value)
+                if GetUserPreferredUILanguages(MUI_LANGUAGE_NAME, ctypes.byref(num), ctypes.byref(buf), ctypes.byref(size)):
+                    return [x.lower() for x in wszarray_to_list(buf)]
+            return None
+
+        else:	# POSIX
+            import locale
+            lang = locale.getdefaultlocale()[0]
+            return lang and [lang.replace('_','-').lower()]
+
+    def respath(self):
+        if getattr(sys, 'frozen', False):
+            if platform=='darwin':
+                return normpath(join(dirname(sys.executable), os.pardir, 'Resources'))
+            else:
+                return dirname(sys.executable)
+        elif __file__:
+            return join(dirname(__file__), 'L10n')
+        else:
+            return 'L10n'
+
+    def file(self, lang):
+        if getattr(sys, 'frozen', False) and platform=='darwin':
+            return codecs.open(join(self.respath(), '%s.lproj' % lang, 'Localizable.strings'), 'r', 'utf-16')
+        else:
+            return codecs.open(join(self.respath(), '%s.strings' % lang), 'r', 'utf-8')
+
+
+# generate template strings file - like xgettext
+# parsing is limited - only single ' or " delimited strings, and only one string per line
+if __name__ == "__main__":
+    import re
+    regexp = re.compile(r'''_\([ur]?(['"])(((?<!\\)\\\1|.)+?)\1\)[^#]*(#.+)?''')	# match a single line python literal
+    seen = {}
+    for f in sorted([x for x in os.listdir('.') if x.endswith('.py')]):
+        with codecs.open(f, 'r', 'utf-8') as h:
+            lineno = 0
+            for line in h:
+                lineno += 1
+                match = regexp.search(line)
+                if match and not match.group(2) in seen:	# only record first instance of a string
+                    seen[match.group(2)] = (match.group(4) and (match.group(4)[1:].strip()) + '. ' or '') + '[%s:%d]' % (f,lineno)
+    if seen:
+        template = codecs.open('L10n/en.template', 'w', 'utf-8')
+        for thing in sorted(seen, key=unicode.lower):
+            if seen[thing]:
+                template.write('/* %s */\n' % (seen[thing]))
+            template.write('"%s" = "%s";\n\n' % (thing, thing))
+        template.close()
diff --git a/prefs.py b/prefs.py
index 45dab303..1c184731 100644
--- a/prefs.py
+++ b/prefs.py
@@ -34,7 +34,8 @@ class PreferencesDialog(tk.Toplevel):
 
         self.parent = parent
         self.callback = callback
-        self.title(platform=='darwin' and 'Preferences' or 'Settings')
+        self.title(platform=='darwin' and _('Preferences') or
+                   _('Settings'))
 
         if parent.winfo_viewable():
             self.transient(parent)
@@ -54,13 +55,13 @@ class PreferencesDialog(tk.Toplevel):
         frame = ttk.Frame(self)
         frame.grid(sticky=tk.NSEW)
 
-        credframe = ttk.LabelFrame(frame, text='Credentials')
+        credframe = ttk.LabelFrame(frame, text=_('Credentials'))	# Section heading in settings
         credframe.grid(padx=10, pady=10, sticky=tk.NSEW)
         credframe.columnconfigure(1, weight=1)
 
-        ttk.Label(credframe, text="Please log in with your Elite: Dangerous account details").grid(row=0, columnspan=2, sticky=tk.W)
-        ttk.Label(credframe, text="Username (Email)").grid(row=1, sticky=tk.W)
-        ttk.Label(credframe, text="Password").grid(row=2, sticky=tk.W)
+        ttk.Label(credframe, text=_('Please log in with your Elite: Dangerous account details')).grid(row=0, columnspan=2, sticky=tk.W)	# Use same text as E:D Launcher's login dialog
+        ttk.Label(credframe, text=_('Username (Email)')).grid(row=1, sticky=tk.W)	# Use same text as E:D Launcher's login dialog
+        ttk.Label(credframe, text=_('Password')).grid(row=2, sticky=tk.W)		# Use same text as E:D Launcher's login dialog
 
         self.username = ttk.Entry(credframe)
         self.username.insert(0, config.get('username') or '')
@@ -73,43 +74,45 @@ class PreferencesDialog(tk.Toplevel):
         for child in credframe.winfo_children():
             child.grid_configure(padx=5, pady=3)
 
-        outframe = ttk.LabelFrame(frame, text='Output')
+        outframe = ttk.LabelFrame(frame, text=_('Output'))		# Section heading in settings
         outframe.grid(padx=10, pady=10, sticky=tk.NSEW)
         outframe.columnconfigure(0, weight=1)
 
         output = config.getint('output') or (config.OUT_EDDN | config.OUT_SHIP_EDS)
-        ttk.Label(outframe, text="Please choose what data to save").grid(row=0, columnspan=2, padx=5, pady=3, sticky=tk.W)
+        ttk.Label(outframe, text=_('Please choose what data to save')).grid(row=0, columnspan=2, padx=5, pady=3, sticky=tk.W)
         self.out_eddn= tk.IntVar(value = (output & config.OUT_EDDN) and 1 or 0)
-        ttk.Checkbutton(outframe, text="Send station data to the Elite Dangerous Data Network", variable=self.out_eddn).grid(row=1, columnspan=2, padx=5, sticky=tk.W)
+        ttk.Checkbutton(outframe, text=_('Send station data to the Elite Dangerous Data Network'), variable=self.out_eddn).grid(row=1, columnspan=2, padx=5, sticky=tk.W)
         self.out_bpc = tk.IntVar(value = (output & config.OUT_BPC ) and 1 or 0)
-        ttk.Checkbutton(outframe, text="Market data in Slopey's BPC format", variable=self.out_bpc, command=self.outvarchanged).grid(row=2, columnspan=2, padx=5, sticky=tk.W)
+        ttk.Checkbutton(outframe, text=_("Market data in Slopey's BPC format"), variable=self.out_bpc, command=self.outvarchanged).grid(row=2, columnspan=2, padx=5, sticky=tk.W)
         self.out_td  = tk.IntVar(value = (output & config.OUT_TD  ) and 1 or 0)
-        ttk.Checkbutton(outframe, text="Market data in Trade Dangerous format", variable=self.out_td, command=self.outvarchanged).grid(row=3, columnspan=2, padx=5, sticky=tk.W)
+        ttk.Checkbutton(outframe, text=_('Market data in Trade Dangerous format'), variable=self.out_td, command=self.outvarchanged).grid(row=3, columnspan=2, padx=5, sticky=tk.W)
         self.out_csv = tk.IntVar(value = (output & config.OUT_CSV ) and 1 or 0)
-        ttk.Checkbutton(outframe, text="Market data in CSV format", variable=self.out_csv, command=self.outvarchanged).grid(row=4, columnspan=2, padx=5, sticky=tk.W)
+        ttk.Checkbutton(outframe, text=_('Market data in CSV format'), variable=self.out_csv, command=self.outvarchanged).grid(row=4, columnspan=2, padx=5, sticky=tk.W)
         self.out_ship_eds= tk.IntVar(value = (output & config.OUT_SHIP_EDS) and 1 or 0)
-        ttk.Checkbutton(outframe, text="Ship loadout in E:D Shipyard format", variable=self.out_ship_eds, command=self.outvarchanged).grid(row=5, columnspan=2, padx=5, sticky=tk.W)
+        ttk.Checkbutton(outframe, text=_('Ship loadout in E:D Shipyard format'), variable=self.out_ship_eds, command=self.outvarchanged).grid(row=5, columnspan=2, padx=5, sticky=tk.W)
         self.out_ship_coriolis= tk.IntVar(value = (output & config.OUT_SHIP_CORIOLIS) and 1 or 0)
-        ttk.Checkbutton(outframe, text="Ship loadout in Coriolis format", variable=self.out_ship_coriolis, command=self.outvarchanged).grid(row=6, columnspan=2, padx=5, sticky=tk.W)
+        ttk.Checkbutton(outframe, text=_('Ship loadout in Coriolis format'), variable=self.out_ship_coriolis, command=self.outvarchanged).grid(row=6, columnspan=2, padx=5, sticky=tk.W)
         self.out_log = tk.IntVar(value = (output & config.OUT_LOG ) and 1 or 0)
-        ttk.Checkbutton(outframe, text="Flight log", variable=self.out_log, command=self.outvarchanged).grid(row=7, columnspan=2, padx=5, sticky=tk.W)
+        ttk.Checkbutton(outframe, text=_('Flight log'), variable=self.out_log, command=self.outvarchanged).grid(row=7, columnspan=2, padx=5, sticky=tk.W)
 
-        ttk.Label(outframe, text=(platform=='darwin' and 'Where:' or 'File location:')).grid(row=8, padx=5, pady=(5,0), sticky=tk.NSEW)
-        self.outbutton = ttk.Button(outframe, text=(platform=='darwin' and 'Change...' or 'Browse...'), command=self.outbrowse)
+        ttk.Label(outframe, text=(platform=='darwin' and _('Where:') or				# Output folder prompt on OSX
+                                  _('File location:'))).grid(row=8, padx=5, pady=(5,0), sticky=tk.NSEW)	# Output folder prompt on Windows
+        self.outbutton = ttk.Button(outframe, text=(platform=='darwin' and _('Change...') or	# Folder selection button on OSX
+                                                    _('Browse...')), command=self.outbrowse)	# Folder selection button on Windows
         self.outbutton.grid(row=8, column=1, padx=5, pady=(5,0), sticky=tk.NSEW)
         self.outdir = ttk.Entry(outframe)
         self.outdir.insert(0, config.get('outdir'))
         self.outdir.grid(row=9, columnspan=2, padx=5, pady=5, sticky=tk.EW)
         self.outvarchanged()
 
-        privacyframe = ttk.LabelFrame(frame, text='Privacy')
+        privacyframe = ttk.LabelFrame(frame, text=_('Privacy'))	# Section heading in settings
         privacyframe.grid(padx=10, pady=10, sticky=tk.NSEW)
         privacyframe.columnconfigure(0, weight=1)
 
         self.out_anon= tk.IntVar(value = config.getint('anonymous') and 1)
-        ttk.Label(privacyframe, text="How do you want to be identified in the saved data").grid(row=0, columnspan=2, padx=5, pady=3, sticky=tk.W)
-        ttk.Radiobutton(privacyframe, text="Cmdr name", variable=self.out_anon, value=0).grid(padx=5, sticky=tk.W)
-        ttk.Radiobutton(privacyframe, text="Pseudo-anonymized ID", variable=self.out_anon, value=1).grid(padx=5, pady=3, sticky=tk.W)
+        ttk.Label(privacyframe, text=_('How do you want to be identified in the saved data')).grid(row=0, columnspan=2, padx=5, pady=3, sticky=tk.W)
+        ttk.Radiobutton(privacyframe, text=_('Cmdr name'), variable=self.out_anon, value=0).grid(padx=5, sticky=tk.W)	# Privacy setting
+        ttk.Radiobutton(privacyframe, text=_('Pseudo-anonymized ID'), variable=self.out_anon, value=1).grid(padx=5, pady=3, sticky=tk.W)	# Privacy setting
 
         if platform=='darwin':
             self.protocol("WM_DELETE_WINDOW", self.apply)	# close button applies changes
@@ -118,7 +121,7 @@ class PreferencesDialog(tk.Toplevel):
             buttonframe.grid(padx=10, pady=10, sticky=tk.NSEW)
             buttonframe.columnconfigure(0, weight=1)
             ttk.Label(buttonframe).grid(row=0, column=0)	# spacer
-            ttk.Button(buttonframe, text='OK', command=self.apply).grid(row=0, column=1, sticky=tk.E)
+            ttk.Button(buttonframe, text=_('OK'), command=self.apply).grid(row=0, column=1, sticky=tk.E)
 
         # wait for window to appear on screen before calling grab_set
         self.wait_visibility()
@@ -202,14 +205,16 @@ class AuthenticationDialog(tk.Toplevel):
         frame.columnconfigure(0, weight=3)
         frame.columnconfigure(2, weight=1)
 
-        ttk.Label(frame, text='A verification code has now been sent to the\nemail address associated with your Elite account.\nPlease enter the code into the box below.', anchor=tk.W, justify=tk.LEFT).grid(columnspan=4, sticky=tk.NSEW)
+        ttk.Label(frame, text=_('A verification code has now been sent to the{CR}email address associated with your Elite account.').format(CR='\n') +	# Use same text as E:D Launcher's verification dialog
+
+                  '\n' +
+                  _('Please enter the code into the box below.'), anchor=tk.W, justify=tk.LEFT).grid(columnspan=4, sticky=tk.NSEW)	# Use same text as E:D Launcher's verification dialog
         ttk.Label(frame).grid(row=1, column=0)	# spacer
-        self.code = ttk.Entry(frame, width=8, validate='key', validatecommand=(self.register(self.validatecode),
-'%P'))
+        self.code = ttk.Entry(frame, width=8, validate='key', validatecommand=(self.register(self.validatecode), '%P'))
         self.code.grid(row=1, column=1)
         self.code.focus_set()
         ttk.Label(frame).grid(row=1, column=2)	# spacer
-        self.button = ttk.Button(frame, text='OK', command=self.apply, state=tk.DISABLED)
+        self.button = ttk.Button(frame, text=_('OK'), command=self.apply, state=tk.DISABLED)
         self.button.grid(row=1, column=3, sticky=tk.E)
 
         for child in frame.winfo_children():
diff --git a/setup.py b/setup.py
index 05385622..007d0c14 100755
--- a/setup.py
+++ b/setup.py
@@ -8,6 +8,7 @@ Usage:
 """
 
 from setuptools import setup
+import codecs
 import os
 from os.path import exists, isdir, join
 import platform
@@ -94,7 +95,8 @@ elif sys.platform=='win32':
                          'WinSparkle.dll',
                          'WinSparkle.pdb',	# For debugging - don't include in package
                          '%s.VisualElementsManifest.xml' % APPNAME,
-                         '%s.ico' % APPNAME ] ) ]
+                         '%s.ico' % APPNAME ] +
+                    [join('L10n',x) for x in os.listdir('L10n') if x.endswith('.strings')] ) ]
 
 setup(
     name = APPLONGNAME,
@@ -117,6 +119,15 @@ setup(
 if sys.platform == 'darwin':
     if isdir('%s/%s.app' % (dist_dir, APPLONGNAME)):	# from CFBundleName
         os.rename('%s/%s.app' % (dist_dir, APPLONGNAME), '%s/%s.app' % (dist_dir, APPNAME))
+
+        # Generate OSX-style localization files
+        for x in os.listdir('L10n'):
+            if x.endswith('.strings'):
+                lang = x[:-len('.strings')]
+                path = '%s/%s.app/Contents/Resources/%s.lproj' % (dist_dir, APPNAME, lang)
+                os.mkdir(path)
+                codecs.open('%s/Localizable.strings' % path, 'w', 'utf-16').write(codecs.open('L10n/%s' % x, 'r', 'utf-8').read())
+
         if macdeveloperid:
             os.system('codesign --deep -v -s "Developer ID Application: %s" %s/%s.app' % (macdeveloperid, dist_dir, APPNAME))
         # Make zip for distribution, preserving signature
diff --git a/update.py b/update.py
index d1d7b2f0..a305b941 100644
--- a/update.py
+++ b/update.py
@@ -74,6 +74,15 @@ elif sys.platform=='win32':
                 self.callback_fn = self.callback_t(shutdown_request)
                 self.updater.win_sparkle_set_shutdown_request_callback(self.callback_fn)
 
+                # Translations require winsparkle 0.5
+                try:
+                    import l10n
+                    langs = l10n.Translations().preferred()
+                    if langs:
+                        self.updater.win_sparkle_set_lang(langs[0])
+                except:
+                    pass
+
                 self.updater.win_sparkle_init()
 
             except: