diff --git a/startupcache/StartupCache.cpp b/startupcache/StartupCache.cpp
index 38fc6152a428..a492e52010a2 100644
--- a/startupcache/StartupCache.cpp
+++ b/startupcache/StartupCache.cpp
@@ -29,7 +29,7 @@
 #include "nsITimer.h"
 #include "mozilla/Omnijar.h"
 #include "prenv.h"
-#include "mozilla/Telemetry.h"
+#include "mozilla/glean/StartupcacheMetrics.h"
 #include "nsThreadUtils.h"
 #include "nsXULAppAPI.h"
 #include "nsIProtocolHandler.h"
@@ -377,10 +377,9 @@ nsresult StartupCache::GetBuffer(const char* id, const char** outbuf,
   NS_ASSERTION(NS_IsMainThread(),
                "Startup cache only available on main thread");
 
-  Telemetry::LABELS_STARTUP_CACHE_REQUESTS label =
-      Telemetry::LABELS_STARTUP_CACHE_REQUESTS::Miss;
-  auto telemetry =
-      MakeScopeExit([&label] { Telemetry::AccumulateCategorical(label); });
+  auto label = glean::startup_cache::RequestsLabel::eMiss;
+  auto telemetry = MakeScopeExit(
+      [&label] { glean::startup_cache::requests.EnumGet(label).Add(); });
 
   MutexAutoLock lock(mTableLock);
   decltype(mTable)::Ptr p = mTable.lookup(nsDependentCString(id));
@@ -390,7 +389,7 @@ nsresult StartupCache::GetBuffer(const char* id, const char** outbuf,
 
   auto& value = p->value();
   if (value.mData) {
-    label = Telemetry::LABELS_STARTUP_CACHE_REQUESTS::HitMemory;
+    label = glean::startup_cache::RequestsLabel::eHitmemory;
   } else {
     if (!mCacheData.initialized()) {
       return NS_ERROR_NOT_AVAILABLE;
@@ -432,7 +431,7 @@ nsresult StartupCache::GetBuffer(const char* id, const char** outbuf,
 
     MMAP_FAULT_HANDLER_CATCH(NS_ERROR_FAILURE)
 
-    label = Telemetry::LABELS_STARTUP_CACHE_REQUESTS::HitDisk;
+    label = glean::startup_cache::RequestsLabel::eHitdisk;
   }
 
   if (!value.mRequested) {
diff --git a/startupcache/metrics.yaml b/startupcache/metrics.yaml
new file mode 100644
index 000000000000..8180627b8fb9
--- /dev/null
+++ b/startupcache/metrics.yaml
@@ -0,0 +1,43 @@
+# 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 :: XPCOM'
+
+startup_cache:
+  requests:
+    type: labeled_counter
+    description: >
+      Record hits and misses to the startup cache, with categories.
+
+      This metric was generated to correspond to the Legacy Telemetry
+      categorical histogram STARTUP_CACHE_REQUESTS.
+    labels:
+      - HitMemory
+      - HitDisk
+      - Miss
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1364235
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1590385
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1623098
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1649954
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1689257
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1754639
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1364235
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1590385
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1623098
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1649954
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1689257
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1754639
+    notification_emails:
+      - dothayer@mozilla.com
+      - plawless@mozilla.com
+    expires: never
+    telemetry_mirror: h#STARTUP_CACHE_REQUESTS
diff --git a/toolkit/components/glean/metrics_index.py b/toolkit/components/glean/metrics_index.py
index d462463a7dc1..8a7e56e7abb8 100644
--- a/toolkit/components/glean/metrics_index.py
+++ b/toolkit/components/glean/metrics_index.py
@@ -65,6 +65,7 @@ gecko_metrics = [
     "security/manager/ssl/metrics.yaml",
     "services/common/metrics.yaml",
     "services/sync/modules/metrics.yaml",
+    "startupcache/metrics.yaml",
     "toolkit/components/antitracking/bouncetrackingprotection/metrics.yaml",
     "toolkit/components/antitracking/metrics.yaml",
     "toolkit/components/captchadetection/metrics.yaml",