diff --git a/toolkit/components/telemetry/Histograms.json b/toolkit/components/telemetry/Histograms.json
index ea2986462d0a..ff4d9b2780a5 100644
--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -8428,6 +8428,22 @@
     "n_buckets": 100,
     "description": "Time taken (in ms) to update the inspector during a page reload, starting from new-root event."
   },
+  "MEDIA_GMP_UPDATE_XML_FETCH_RESULT": {
+    "record_in_processes": ["main"],
+    "products": ["firefox"],
+    "alert_emails": ["media-alerts@mozilla.com"],
+    "expires_in_version": "never",
+    "releaseChannelCollection": "opt-out",
+    "kind": "categorical",
+    "labels": [
+      "cert_pinning_ok",
+      "cert_pinning_fail",
+      "content_sig_ok",
+      "content_sig_fail"
+    ],
+    "description": "Reports if a Firefox succeeded or failed in fetching the GMP update.xml from balrog, and which method was used to verify the download.",
+    "bug_numbers": [1714621]
+  },
   "MEDIA_MP4_PARSE_SAMPLE_DESCRIPTION_ENTRIES_HAVE_MULTIPLE_CODECS": {
     "record_in_processes": ["main", "content"],
     "products": ["firefox", "fennec"],
diff --git a/toolkit/modules/GMPInstallManager.sys.mjs b/toolkit/modules/GMPInstallManager.sys.mjs
index 2299f3b9c3b5..c73bd65df919 100644
--- a/toolkit/modules/GMPInstallManager.sys.mjs
+++ b/toolkit/modules/GMPInstallManager.sys.mjs
@@ -229,11 +229,19 @@ GMPInstallManager.prototype = {
       "GMPInstallManager.recordUpdateXmlTelemetryForContentSignature"
     );
     try {
+      let updateResultHistogram = Services.telemetry.getHistogramById(
+        "MEDIA_GMP_UPDATE_XML_FETCH_RESULT"
+      );
+
+      // The non-glean telemetry used here will be removed in future and just
+      // the glean data will be gathered.
       if (didGetAddonList) {
+        updateResultHistogram.add("content_sig_ok");
         Glean.gmp.updateXmlFetchResult.content_sig_success.add(1);
         return;
       }
       // All remaining cases are failure cases.
+      updateResultHistogram.add("content_sig_fail");
       if (!err?.addonCheckerErr) {
         // Unknown error case. If this is happening we should audit error paths
         // to identify why we're not getting an error, or not getting it
@@ -283,11 +291,19 @@ GMPInstallManager.prototype = {
       "GMPInstallManager.recordUpdateXmlTelemetryForCertPinning"
     );
     try {
+      let updateResultHistogram = Services.telemetry.getHistogramById(
+        "MEDIA_GMP_UPDATE_XML_FETCH_RESULT"
+      );
+
+      // The non-glean telemetry used here will be removed in future and just
+      // the glean data will be gathered.
       if (didGetAddonList) {
+        updateResultHistogram.add("cert_pinning_ok");
         Glean.gmp.updateXmlFetchResult.cert_pin_success.add(1);
         return;
       }
       // All remaining cases are failure cases.
+      updateResultHistogram.add("cert_pinning_fail");
       if (!err?.addonCheckerErr) {
         // Unknown error case. If this is happening we should audit error paths
         // to identify why we're not getting an error, or not getting it
diff --git a/toolkit/modules/tests/xpcshell/test_GMPInstallManager.js b/toolkit/modules/tests/xpcshell/test_GMPInstallManager.js
index ee09781ac058..21a15c4c917f 100644
--- a/toolkit/modules/tests/xpcshell/test_GMPInstallManager.js
+++ b/toolkit/modules/tests/xpcshell/test_GMPInstallManager.js
@@ -20,6 +20,9 @@ const { HttpServer } = ChromeUtils.importESModule(
 const { Preferences } = ChromeUtils.importESModule(
   "resource://gre/modules/Preferences.sys.mjs"
 );
+const { TelemetryTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/TelemetryTestUtils.sys.mjs"
+);
 const { UpdateUtils } = ChromeUtils.importESModule(
   "resource://gre/modules/UpdateUtils.sys.mjs"
 );
@@ -561,7 +564,7 @@ add_task(async function test_checkForAddons_updatesWithAddons() {
 add_task(async function test_checkForAddons_contentSignatureSuccess() {
   const previousUrlOverride = setupContentSigTestPrefs();
 
-  Services.fog.testResetFOG();
+  const xmlFetchResultHistogram = resetGmpTelemetryAndGetHistogram();
 
   const testServerInfo = getTestServerForContentSignatureTests();
   Preferences.set(GMPPrefs.KEY_URL_OVERRIDE, testServerInfo.validUpdateUri);
@@ -606,6 +609,8 @@ add_task(async function test_checkForAddons_contentSignatureSuccess() {
     Assert.ok(false, "checkForAddons should succeed");
   }
 
+  // # Ok content sig fetches should be 1, all others should be 0.
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 2, 1);
   // Test that glean has 1 success for content sig and no other metrics.
   const expectedGleanValues = {
     cert_pin_success: 0,
@@ -637,7 +642,7 @@ add_task(async function test_checkForAddons_contentSignatureSuccess() {
 add_task(async function test_checkForAddons_contentSignatureFailure() {
   const previousUrlOverride = setupContentSigTestPrefs();
 
-  Services.fog.testResetFOG();
+  const xmlFetchResultHistogram = resetGmpTelemetryAndGetHistogram();
 
   const testServerInfo = getTestServerForContentSignatureTests();
   Preferences.set(
@@ -692,6 +697,8 @@ add_task(async function test_checkForAddons_contentSignatureFailure() {
     Assert.ok(false, "checkForAddons should succeed");
   }
 
+  // # Failed content sig fetches should be 1, all others should be 0.
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 3, 1);
   // Glean values should reflect the content sig algo failed.
   Assert.equal(
     Glean.gmp.updateXmlFetchResult.content_sig_missing_data.testGetValue(),
@@ -704,8 +711,10 @@ add_task(async function test_checkForAddons_contentSignatureFailure() {
   // Fail due to bad content signature.
   Preferences.set(GMPPrefs.KEY_URL_OVERRIDE, testServerInfo.badContentSigUri);
   await installManager.checkForAddons();
-  // Should have another failure and it should be due to the signature being bad,
-  // which causes verification to fail.
+  // Should have another failure...
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 3, 2);
+  // ... and it should be due to the signature being bad, which causes
+  // verification to fail.
   Assert.equal(
     Glean.gmp.updateXmlFetchResult.content_sig_failed.testGetValue(),
     1
@@ -717,7 +726,9 @@ add_task(async function test_checkForAddons_contentSignatureFailure() {
     testServerInfo.invalidContentSigUri
   );
   await installManager.checkForAddons();
-  // Should have another failure and it should be due to the signature being invalid.
+  // Should have another failure...
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 3, 3);
+  // ... and it should be due to the signature being invalid.
   Assert.equal(
     Glean.gmp.updateXmlFetchResult.content_sig_invalid.testGetValue(),
     1
@@ -729,7 +740,9 @@ add_task(async function test_checkForAddons_contentSignatureFailure() {
     "https://this.url.doesnt/go/anywhere"
   );
   await installManager.checkForAddons();
-  // Should have another failure and it should be due to a bad request.
+  // Should have another failure...
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 3, 4);
+  // ... and it should be due to a bad request.
   Assert.equal(
     Glean.gmp.updateXmlFetchResult.content_sig_net_request_error.testGetValue(),
     1
@@ -746,7 +759,8 @@ add_task(async function test_checkForAddons_contentSignatureFailure() {
     overriddenServiceRequest,
     () => installManager.checkForAddons()
   );
-  // Should have another failure and it should be due to a timeout.
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 3, 5);
+  // ... and it should be due to a timeout.
   Assert.equal(
     Glean.gmp.updateXmlFetchResult.content_sig_net_timeout.testGetValue(),
     1
@@ -766,7 +780,9 @@ add_task(async function test_checkForAddons_contentSignatureFailure() {
     overriddenServiceRequest.abort();
   }, 100);
   await promise;
-  // Should have another failure and it should be due to an abort.
+  // Should have another failure...
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 3, 6);
+  // ... and it should be due to an abort.
   Assert.equal(
     Glean.gmp.updateXmlFetchResult.content_sig_abort.testGetValue(),
     1
@@ -774,8 +790,9 @@ add_task(async function test_checkForAddons_contentSignatureFailure() {
 
   Preferences.set(GMPPrefs.KEY_URL_OVERRIDE, testServerInfo.badXmlUri);
   await installManager.checkForAddons();
-  // Should have another failure and it should be due to the xml response being
-  // unrecognized.
+  // Should have another failure...
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 3, 7);
+  // ... and it should be due to the xml response being unrecognized.
   Assert.equal(
     Glean.gmp.updateXmlFetchResult.content_sig_xml_parse_error.testGetValue(),
     1
@@ -784,7 +801,9 @@ add_task(async function test_checkForAddons_contentSignatureFailure() {
   // Fail via bad request during the x5u look up.
   Preferences.set(GMPPrefs.KEY_URL_OVERRIDE, testServerInfo.badX5uRequestUri);
   await installManager.checkForAddons();
-  // Should have another failure and it should be due to a bad request.
+  // Should have another failure...
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 3, 8);
+  // ... and it should be due to a bad request.
   Assert.equal(
     Glean.gmp.updateXmlFetchResult.content_sig_net_request_error.testGetValue(),
     2
@@ -801,7 +820,9 @@ add_task(async function test_checkForAddons_contentSignatureFailure() {
   await testServerInfo.promiseHolder.serverPromise;
   delete testServerInfo.promiseHolder.installPromise;
   delete testServerInfo.promiseHolder.serverPromise;
-  // Should have another failure and it should be due to a timeout.
+  // Should have another failure...
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 3, 9);
+  // ... and it should be due to a timeout.
   Assert.equal(
     Glean.gmp.updateXmlFetchResult.content_sig_net_timeout.testGetValue(),
     2
@@ -818,7 +839,9 @@ add_task(async function test_checkForAddons_contentSignatureFailure() {
   await testServerInfo.promiseHolder.serverPromise;
   delete testServerInfo.promiseHolder.installPromise;
   delete testServerInfo.promiseHolder.serverPromise;
-  // Should have another failure and it should be due to an abort.
+  // Should have another failure...
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 3, 10);
+  // ... and it should be due to an abort.
   Assert.equal(
     Glean.gmp.updateXmlFetchResult.content_sig_abort.testGetValue(),
     2
@@ -915,7 +938,7 @@ add_task(async function test_checkForAddons_telemetry_certPinning() {
   // Grab state so we can restore it at the end of the test.
   const previousUrlOverride = Preferences.get(GMPPrefs.KEY_URL_OVERRIDE, "");
 
-  Services.fog.testResetFOG();
+  let xmlFetchResultHistogram = resetGmpTelemetryAndGetHistogram();
 
   // Re-use the content-sig test server config. We're not going to need any of
   // the content signature specific config but this gives us a server to get
@@ -936,19 +959,27 @@ add_task(async function test_checkForAddons_telemetry_certPinning() {
     Assert.ok(false, "checkForAddons should succeed");
   }
 
-  // Glean values should reflect 1 successful pin fetch.
+  // # Ok cert pin fetches should be 1, all others should be 0.
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 0, 1);
+  // Glean values should reflect the same.
   Assert.equal(
     Glean.gmp.updateXmlFetchResult.cert_pin_success.testGetValue(),
     1
   );
 
+  // Reset the histogram because we want to check a different index.
+  xmlFetchResultHistogram = TelemetryTestUtils.getAndClearHistogram(
+    "MEDIA_GMP_UPDATE_XML_FETCH_RESULT"
+  );
   // Fail by pointing to a bad URL.
   Preferences.set(
     GMPPrefs.KEY_URL_OVERRIDE,
     "https://this.url.doesnt/go/anywhere"
   );
   await installManager.checkForAddons();
-  // Should have another failure and it should be due to a bad request.
+  // Should have another failure...
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 1, 1);
+  // ... and it should be due to a bad request.
   Assert.equal(
     Glean.gmp.updateXmlFetchResult.cert_pin_net_request_error.testGetValue(),
     1
@@ -965,7 +996,8 @@ add_task(async function test_checkForAddons_telemetry_certPinning() {
     overriddenServiceRequest,
     () => installManager.checkForAddons()
   );
-  // Should have another failure and it should be due to a timeout.
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 1, 2);
+  // ... and it should be due to a timeout.
   Assert.equal(
     Glean.gmp.updateXmlFetchResult.cert_pin_net_timeout.testGetValue(),
     1
@@ -985,7 +1017,9 @@ add_task(async function test_checkForAddons_telemetry_certPinning() {
     overriddenServiceRequest.abort();
   }, 100);
   await promise;
-  // Should have another failure and it should be due to an abort.
+  // Should have another failure...
+  TelemetryTestUtils.assertHistogram(xmlFetchResultHistogram, 1, 3);
+  // ... and it should be due to an abort.
   Assert.equal(Glean.gmp.updateXmlFetchResult.cert_pin_abort.testGetValue(), 1);
 
   // Check all glean metrics have expected values at test end.
@@ -1918,6 +1952,19 @@ function revertContentSigTestPrefs(previousUrlOverride) {
   Preferences.set("media.gmp-manager.checkContentSignature", false);
 }
 
+/***
+ * Reset telemetry data related to gmp updates, and get the histogram
+ * associated with MEDIA_GMP_UPDATE_XML_FETCH_RESULT.
+ *
+ * @returns The freshly cleared MEDIA_GMP_UPDATE_XML_FETCH_RESULT histogram.
+ */
+function resetGmpTelemetryAndGetHistogram() {
+  Services.fog.testResetFOG();
+  return TelemetryTestUtils.getAndClearHistogram(
+    "MEDIA_GMP_UPDATE_XML_FETCH_RESULT"
+  );
+}
+
 /***
  * A helper to check that glean metrics have expected counts.
  * @param expectedGleanValues a object that has properties with names set to glean metrics to be checked