diff --git a/onionshare/settings.py b/onionshare/settings.py
index adcfc7a3..d231a976 100644
--- a/onionshare/settings.py
+++ b/onionshare/settings.py
@@ -21,6 +21,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 import json
 import os
 import platform
+import locale
 
 from . import strings
 
@@ -47,6 +48,12 @@ class Settings(object):
             else:
                 self.common.log('Settings', '__init__', 'Supplied config does not exist or is unreadable. Falling back to default location')
 
+        # Available languages in this version of OnionShare
+        self.available_locales = [
+            'cs', 'da', 'de', 'en', 'eo', 'es', 'fi',
+            'fr', 'it', 'nl', 'no', 'pt', 'ru', 'tr'
+        ]
+
         # These are the default settings. They will get overwritten when loading from disk
         self.default_settings = {
             'version': self.common.version,
@@ -74,7 +81,8 @@ class Settings(object):
             'slug': '',
             'hidservauth_string': '',
             'downloads_dir': self.build_default_downloads_dir(),
-            'receive_allow_receiver_shutdown': True
+            'receive_allow_receiver_shutdown': True,
+            'locale': None # this gets defined in fill_in_defaults()
         }
         self._settings = {}
         self.fill_in_defaults()
@@ -88,6 +96,13 @@ class Settings(object):
             if key not in self._settings:
                 self._settings[key] = self.default_settings[key]
 
+        # Choose the default locale based on the OS preference, and fall-back to English
+        if self._settings['locale'] is None:
+            default_locale = locale.getdefaultlocale()[0][:2]
+            if default_locale not in self.available_locales:
+                default_locale = 'en'
+            self._settings['locale'] = default_locale
+
     def build_filename(self):
         """
         Returns the path of the settings file.
diff --git a/tests/test_onionshare_settings.py b/tests/test_onionshare_settings.py
index 1f1ef528..371b2d27 100644
--- a/tests/test_onionshare_settings.py
+++ b/tests/test_onionshare_settings.py
@@ -40,7 +40,7 @@ def settings_obj(sys_onionshare_dev_mode, platform_linux):
 
 class TestSettings:
     def test_init(self, settings_obj):
-        assert settings_obj._settings == settings_obj.default_settings == {
+        expected_settings = {
             'version': 'DUMMY_VERSION_1.2.3',
             'connection_type': 'bundled',
             'control_port_address': '127.0.0.1',
@@ -68,6 +68,11 @@ class TestSettings:
             'receive_allow_receiver_shutdown': True,
             'public_mode': False
         }
+        for key in settings_obj._settings:
+            # Skip locale, it will not always default to the same thing
+            if key != 'locale':
+                assert settings_obj._settings[key] == settings_obj.default_settings[key]
+                assert settings_obj._settings[key] == expected_settings[key]
 
     def test_fill_in_defaults(self, settings_obj):
         del settings_obj._settings['version']