diff --git a/pkgs/applications/networking/browsers/firefox/common.nix b/pkgs/applications/networking/browsers/firefox/common.nix
index 217b4e323886..06bfddd1d8d9 100644
--- a/pkgs/applications/networking/browsers/firefox/common.nix
+++ b/pkgs/applications/networking/browsers/firefox/common.nix
@@ -103,6 +103,7 @@
 , crashreporterSupport ? !privacySupport
 , geolocationSupport ? !privacySupport
 , googleAPISupport ? geolocationSupport
+, mlsAPISupport ? geolocationSupport
 , webrtcSupport ? !privacySupport
 
 # digital rights managemewnt
@@ -185,6 +186,18 @@ let
     };
   });
 
+  defaultPrefs = {
+    "geo.provider.network.url" = {
+      value = "https://location.services.mozilla.com/v1/geolocate?key=%MOZILLA_API_KEY%";
+      reason = "Use MLS by default for geolocation, since our Google API Keys are not working";
+    };
+  };
+
+  defaultPrefsFile = pkgs.writeText "nixos-default-prefs.js" (lib.concatStringsSep "\n" (lib.mapAttrsToList (key: value: ''
+    // ${value.reason}
+    pref("${key}", ${builtins.toJSON value.value});
+  '') defaultPrefs));
+
 in
 
 buildStdenv.mkDerivation ({
@@ -304,11 +317,17 @@ buildStdenv.mkDerivation ({
   '' + lib.optionalString googleAPISupport ''
     # Google API key used by Chromium and Firefox.
     # Note: These are for NixOS/nixpkgs use ONLY. For your own distribution,
-    # please get your own set of keys.
-    echo "AIzaSyDGi15Zwl11UNe6Y-5XW_upsfyw31qwZPI" > $TMPDIR/ga
+    # please get your own set of keys at https://www.chromium.org/developers/how-tos/api-keys/.
+    echo "AIzaSyDGi15Zwl11UNe6Y-5XW_upsfyw31qwZPI" > $TMPDIR/google-api-key
     # 60.5+ & 66+ did split the google API key arguments: https://bugzilla.mozilla.org/show_bug.cgi?id=1531176
-    configureFlagsArray+=("--with-google-location-service-api-keyfile=$TMPDIR/ga")
-    configureFlagsArray+=("--with-google-safebrowsing-api-keyfile=$TMPDIR/ga")
+    configureFlagsArray+=("--with-google-location-service-api-keyfile=$TMPDIR/google-api-key")
+    configureFlagsArray+=("--with-google-safebrowsing-api-keyfile=$TMPDIR/google-api-key")
+  '' + lib.optionalString mlsAPISupport ''
+    # Mozilla Location services API key
+    # Note: These are for NixOS/nixpkgs use ONLY. For your own distribution,
+    # please get your own set of keys at https://location.services.mozilla.com/api.
+    echo "dfd7836c-d458-4917-98bb-421c82d3c8a0" > $TMPDIR/mls-api-key
+    configureFlagsArray+=("--with-mozilla-api-keyfile=$TMPDIR/mls-api-key")
   '' + lib.optionalString enableOfficialBranding ''
     export MOZILLA_OFFICIAL=1
   '';
@@ -467,6 +486,7 @@ buildStdenv.mkDerivation ({
   postInstall = ''
     # Install distribution customizations
     install -Dvm644 ${distributionIni} $out/lib/${binaryName}/distribution/distribution.ini
+    install -Dvm644 ${defaultPrefsFile} $out/lib/${binaryName}/browser/defaults/preferences/nixos-default-prefs.js
 
   '' + lib.optionalString buildStdenv.isLinux ''
     # Remove SDK cruft. FIXME: move to a separate output?