diff --git a/intl/locale/metrics.yaml b/intl/locale/metrics.yaml
new file mode 100644
index 000000000000..3fd6f44c80b3
--- /dev/null
+++ b/intl/locale/metrics.yaml
@@ -0,0 +1,103 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Adding a new metric? We have docs for that!
+# https://firefox-source-docs.mozilla.org/toolkit/components/glean/user/new_definitions_file.html
+
+---
+$schema: moz://mozilla.org/schemas/glean/metrics/2-0-0
+$tags:
+  - 'Core :: Internationalization'
+
+intl:
+  requested_locales:
+    type: string_list
+    lifetime: application
+    description: |
+      The Locales that are being requested.
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1950394
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1950394
+    data_sensitivity:
+      - technical
+    notification_emails:
+      - flod@mozilla.com
+    expires: never
+
+  available_locales:
+    type: string_list
+    lifetime: application
+    description: |
+      The Locales that are available for use.
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1950394
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1950394
+    data_sensitivity:
+      - technical
+    notification_emails:
+      - flod@mozilla.com
+    expires: never
+
+  app_locales:
+    type: string_list
+    lifetime: application
+    description: |
+      The negotiated Locales that are being used.
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1950394
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1950394
+    data_sensitivity:
+      - technical
+    notification_emails:
+      - flod@mozilla.com
+    expires: never
+
+  system_locales:
+    type: string_list
+    lifetime: application
+    description: |
+      The Locales for the OS.
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1950394
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1950394
+    data_sensitivity:
+      - technical
+    notification_emails:
+      - flod@mozilla.com
+    expires: never
+
+  regional_prefs_locales:
+    type: string_list
+    lifetime: application
+    description: |
+      The regional preferences for the OS.
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1950394
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1950394
+    data_sensitivity:
+      - technical
+    notification_emails:
+      - flod@mozilla.com
+    expires: never
+
+  accept_languages:
+    type: string_list
+    lifetime: application
+    description: |
+      The languages for the Accept-Languages header.
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1950394
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1950394
+    data_sensitivity:
+      - technical
+    notification_emails:
+      - flod@mozilla.com
+    expires: never
+
diff --git a/toolkit/components/glean/metrics_index.py b/toolkit/components/glean/metrics_index.py
index e1a63afd319d..89c3c4ef03ff 100644
--- a/toolkit/components/glean/metrics_index.py
+++ b/toolkit/components/glean/metrics_index.py
@@ -49,6 +49,7 @@ gecko_metrics = [
     "extensions/permissions/metrics.yaml",
     "gfx/metrics.yaml",
     "image/decoders/metrics.yaml",
+    "intl/locale/metrics.yaml",
     "ipc/metrics.yaml",
     "js/xpconnect/metrics.yaml",
     "layout/base/metrics.yaml",
diff --git a/toolkit/components/telemetry/app/TelemetryEnvironment.sys.mjs b/toolkit/components/telemetry/app/TelemetryEnvironment.sys.mjs
index 90e8711f6806..9363388c7f7e 100644
--- a/toolkit/components/telemetry/app/TelemetryEnvironment.sys.mjs
+++ b/toolkit/components/telemetry/app/TelemetryEnvironment.sys.mjs
@@ -82,8 +82,8 @@ export var Policy = {
 var gActiveExperimentStartupBuffer = new Map();
 
 // For Powering arewegleanyet.com (See bug 1944592)
-// Legacy Count: 115
-// Glean Count: 111
+// Legacy Count: 118
+// Glean Count: 117
 
 var gGlobalEnvironment;
 function getGlobal() {
@@ -479,7 +479,7 @@ function getRegionalPrefsLocales() {
 }
 
 function getIntlSettings() {
-  return {
+  let intl = {
     requestedLocales: Services.locale.requestedLocales,
     availableLocales: Services.locale.availableLocales,
     appLocales: Services.locale.appLocalesAsBCP47,
@@ -490,6 +490,13 @@ function getIntlSettings() {
       .data.split(",")
       .map(str => str.trim()),
   };
+  Glean.intl.requestedLocales.set(intl.requestedLocales);
+  Glean.intl.availableLocales.set(intl.availableLocales);
+  Glean.intl.appLocales.set(intl.appLocales);
+  Glean.intl.systemLocales.set(intl.systemLocales);
+  Glean.intl.regionalPrefsLocales.set(intl.regionalPrefsLocales);
+  Glean.intl.acceptLanguages.set(intl.acceptLanguages);
+  return intl;
 }
 
 /**
diff --git a/toolkit/components/telemetry/tests/unit/TelemetryEnvironmentTesting.sys.mjs b/toolkit/components/telemetry/tests/unit/TelemetryEnvironmentTesting.sys.mjs
index 001fc4a52452..c08daea84141 100644
--- a/toolkit/components/telemetry/tests/unit/TelemetryEnvironmentTesting.sys.mjs
+++ b/toolkit/components/telemetry/tests/unit/TelemetryEnvironmentTesting.sys.mjs
@@ -431,6 +431,7 @@ export var TelemetryEnvironmentTesting = {
 
     for (let field of fields) {
       lazy.Assert.ok(Array.isArray(intl[field]), `${field} is an array`);
+      lazy.Assert.deepEqual(intl[field], Glean.intl[field].testGetValue());
     }
 
     // These fields may be null if they aren't ready yet. This is mostly to deal
@@ -441,6 +442,7 @@ export var TelemetryEnvironmentTesting = {
       let isArray = Array.isArray(intl[field]);
       let isNull = intl[field] === null;
       lazy.Assert.ok(isArray || isNull, `${field} is an array or null`);
+      lazy.Assert.deepEqual(intl[field], Glean.intl[field].testGetValue());
     }
   },