diff --git a/.eslintignore b/.eslintignore
index 883e6dae8654..37c1e5280539 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -37,8 +37,8 @@ browser/components/sessionstore/test/unit/data/sessionstore_valid.js
 browser/components/sessionstore/test/unit/data/sessionstore_invalid.js
 # This file is split into two in order to keep it as a valid json file
 # for documentation purposes (policies.json) but to be accessed by the
-# code as a .jsm (schema.jsm)
-browser/components/enterprisepolicies/schemas/schema.jsm
+# code as a .sys.mjs (schema.sys.mjs)
+browser/components/enterprisepolicies/schemas/schema.sys.mjs
 # generated or library files in pocket
 browser/components/pocket/content/panels/js/tmpl.js
 browser/components/pocket/content/panels/js/vendor.bundle.js
diff --git a/.prettierignore b/.prettierignore
index 12101edba09a..30db2098f393 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -101,8 +101,8 @@ browser/components/sessionstore/test/unit/data/sessionstore_valid.js
 browser/components/sessionstore/test/unit/data/sessionstore_invalid.js
 # This file is split into two in order to keep it as a valid json file
 # for documentation purposes (policies.json) but to be accessed by the
-# code as a .jsm (schema.jsm)
-browser/components/enterprisepolicies/schemas/schema.jsm
+# code as a .sys.mjs (schema.sys.mjs)
+browser/components/enterprisepolicies/schemas/schema.sys.mjs
 # generated or library files in pocket
 browser/components/pocket/content/panels/js/tmpl.js
 browser/components/pocket/content/panels/js/vendor.bundle.js
diff --git a/browser/components/enterprisepolicies/content/aboutPolicies.js b/browser/components/enterprisepolicies/content/aboutPolicies.js
index 705ceccfd81b..a20ebfc351b3 100644
--- a/browser/components/enterprisepolicies/content/aboutPolicies.js
+++ b/browser/components/enterprisepolicies/content/aboutPolicies.js
@@ -8,8 +8,8 @@ const { XPCOMUtils } = ChromeUtils.importESModule(
   "resource://gre/modules/XPCOMUtils.sys.mjs"
 );
 
-XPCOMUtils.defineLazyModuleGetters(this, {
-  schema: "resource:///modules/policies/schema.jsm",
+ChromeUtils.defineESModuleGetters(this, {
+  schema: "resource:///modules/policies/schema.sys.mjs",
 });
 
 function col(text, className) {
diff --git a/browser/components/enterprisepolicies/schemas/moz.build b/browser/components/enterprisepolicies/schemas/moz.build
index 19e17705e798..47b6fbee19cf 100644
--- a/browser/components/enterprisepolicies/schemas/moz.build
+++ b/browser/components/enterprisepolicies/schemas/moz.build
@@ -8,5 +8,5 @@ with Files("**"):
     BUG_COMPONENT = ("Firefox", "Enterprise Policies")
 
 EXTRA_PP_JS_MODULES.policies += [
-    "schema.jsm",
+    "schema.sys.mjs",
 ]
diff --git a/browser/components/enterprisepolicies/schemas/schema.jsm b/browser/components/enterprisepolicies/schemas/schema.sys.mjs
similarity index 52%
rename from browser/components/enterprisepolicies/schemas/schema.jsm
rename to browser/components/enterprisepolicies/schemas/schema.sys.mjs
index 54ae8751aa93..3d8ce82385dc 100644
--- a/browser/components/enterprisepolicies/schemas/schema.jsm
+++ b/browser/components/enterprisepolicies/schemas/schema.sys.mjs
@@ -2,9 +2,15 @@
  * 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/. */
 
-"use strict";
-
-const EXPORTED_SYMBOLS = ["schema"];
-
-const schema =
+const initialSchema =
 #include policies-schema.json
+
+export let schema = initialSchema;
+
+export function modifySchemaForTests(customSchema) {
+    if (customSchema) {
+        schema = customSchema;
+    } else {
+        schema = initialSchema;
+    }
+ }
diff --git a/browser/components/enterprisepolicies/tests/xpcshell/test_sorted_alphabetically.js b/browser/components/enterprisepolicies/tests/xpcshell/test_sorted_alphabetically.js
index b56a69a1b3ff..088e4fcb7e05 100644
--- a/browser/components/enterprisepolicies/tests/xpcshell/test_sorted_alphabetically.js
+++ b/browser/components/enterprisepolicies/tests/xpcshell/test_sorted_alphabetically.js
@@ -19,8 +19,8 @@ function checkArrayIsSorted(array, msg) {
 }
 
 add_task(async function test_policies_sorted() {
-  let { schema } = ChromeUtils.import(
-    "resource:///modules/policies/schema.jsm"
+  let { schema } = ChromeUtils.importESModule(
+    "resource:///modules/policies/schema.sys.mjs"
   );
   let { Policies } = ChromeUtils.importESModule(
     "resource:///modules/policies/Policies.sys.mjs"
@@ -37,8 +37,8 @@ add_task(async function test_policies_sorted() {
 });
 
 add_task(async function check_naming_conventions() {
-  let { schema } = ChromeUtils.import(
-    "resource:///modules/policies/schema.jsm"
+  let { schema } = ChromeUtils.importESModule(
+    "resource:///modules/policies/schema.sys.mjs"
   );
   equal(
     Object.keys(schema.properties).some(key => key.includes("__")),
diff --git a/browser/components/urlbar/tests/ext/api.js b/browser/components/urlbar/tests/ext/api.js
index 51a2757b5a81..77da790190c8 100644
--- a/browser/components/urlbar/tests/ext/api.js
+++ b/browser/components/urlbar/tests/ext/api.js
@@ -103,7 +103,7 @@ this.experiments_urlbar = class extends ExtensionAPI {
           value: Preferences.get(pref),
 
           // Nothing actually uses this, but on debug builds there are extra
-          // checks enabled in Schema.jsm that fail if it's not present.  The
+          // checks enabled in Schema.sys.mjs that fail if it's not present.  The
           // value doesn't matter.
           levelOfControl: "controllable_by_this_extension",
         };
diff --git a/netwerk/test/unit/xpcshell.ini b/netwerk/test/unit/xpcshell.ini
index a6b214d8fedf..4682b7737cc7 100644
--- a/netwerk/test/unit/xpcshell.ini
+++ b/netwerk/test/unit/xpcshell.ini
@@ -678,7 +678,7 @@ skip-if = os == "android"
 run-sequentially = node server exceptions dont replay well
 [test_proxy_pac.js]
 [test_trr_enterprise_policy.js]
-firefox-appdir = browser # needed for resource:///modules/policies/schema.jsm to be registered
+firefox-appdir = browser # needed for resource:///modules/policies/schema.sys.mjs to be registered
 skip-if =
   os == "android"
   socketprocess_networking
diff --git a/toolkit/components/enterprisepolicies/EnterprisePoliciesParent.sys.mjs b/toolkit/components/enterprisepolicies/EnterprisePoliciesParent.sys.mjs
index 0a0c9601be5c..94ddeb07c303 100644
--- a/toolkit/components/enterprisepolicies/EnterprisePoliciesParent.sys.mjs
+++ b/toolkit/components/enterprisepolicies/EnterprisePoliciesParent.sys.mjs
@@ -170,8 +170,8 @@ EnterprisePoliciesManager.prototype = {
   },
 
   _activatePolicies(unparsedPolicies) {
-    let { schema } = ChromeUtils.import(
-      "resource:///modules/policies/schema.jsm"
+    let { schema } = ChromeUtils.importESModule(
+      "resource:///modules/policies/schema.sys.mjs"
     );
 
     for (let policyName of Object.keys(unparsedPolicies)) {
diff --git a/toolkit/components/enterprisepolicies/macOSPoliciesParser.sys.mjs b/toolkit/components/enterprisepolicies/macOSPoliciesParser.sys.mjs
index db2793a6ab20..09f67bba636f 100644
--- a/toolkit/components/enterprisepolicies/macOSPoliciesParser.sys.mjs
+++ b/toolkit/components/enterprisepolicies/macOSPoliciesParser.sys.mjs
@@ -41,8 +41,8 @@ export var macOSPoliciesParser = {
   },
 
   removeUnknownPolicies(policies) {
-    let { schema } = ChromeUtils.import(
-      "resource:///modules/policies/schema.jsm"
+    let { schema } = ChromeUtils.importESModule(
+      "resource:///modules/policies/schema.sys.mjs"
     );
 
     for (let policyName of Object.keys(policies)) {
diff --git a/toolkit/components/enterprisepolicies/tests/EnterprisePolicyTesting.sys.mjs b/toolkit/components/enterprisepolicies/tests/EnterprisePolicyTesting.sys.mjs
index f4432c938632..b877c6f73881 100644
--- a/toolkit/components/enterprisepolicies/tests/EnterprisePolicyTesting.sys.mjs
+++ b/toolkit/components/enterprisepolicies/tests/EnterprisePolicyTesting.sys.mjs
@@ -9,6 +9,7 @@ import { Assert } from "resource://testing-common/Assert.sys.mjs";
 const lazy = {};
 ChromeUtils.defineESModuleGetters(lazy, {
   FileTestUtils: "resource://testing-common/FileTestUtils.sys.mjs",
+  modifySchemaForTests: "resource:///modules/policies/schema.sys.mjs",
 });
 
 export var EnterprisePolicyTesting = {
@@ -41,15 +42,8 @@ export var EnterprisePolicyTesting = {
       }, "EnterprisePolicies:AllPoliciesApplied");
     });
 
-    // Clear any previously used custom schema
-    Cu.unload("resource:///modules/policies/schema.jsm");
-
-    if (customSchema) {
-      let schemaModule = ChromeUtils.import(
-        "resource:///modules/policies/schema.jsm"
-      );
-      schemaModule.schema = customSchema;
-    }
+    // Clear any previously used custom schema or assign a new one
+    lazy.modifySchemaForTests(customSchema || null);
 
     Services.obs.notifyObservers(null, "EnterprisePolicies:Restart");
     return promise;
diff --git a/toolkit/components/enterprisepolicies/tests/xpcshell/xpcshell.ini b/toolkit/components/enterprisepolicies/tests/xpcshell/xpcshell.ini
index b5ba816b2611..234dcb03c8df 100644
--- a/toolkit/components/enterprisepolicies/tests/xpcshell/xpcshell.ini
+++ b/toolkit/components/enterprisepolicies/tests/xpcshell/xpcshell.ini
@@ -1,4 +1,5 @@
 [DEFAULT]
+firefox-appdir = browser
 head = head.js
 skip-if = toolkit == 'android'
 
diff --git a/tools/esmify/mach_commands.py b/tools/esmify/mach_commands.py
index 6d1fb71d5b07..787de484244b 100644
--- a/tools/esmify/mach_commands.py
+++ b/tools/esmify/mach_commands.py
@@ -120,7 +120,7 @@ excluded_from_imports_prefix = list(
             # Files has macro.
             "browser/app/profile/firefox.js",
             "browser/branding/official/pref/firefox-branding.js",
-            "browser/components/enterprisepolicies/schemas/schema.jsm",
+            "browser/components/enterprisepolicies/schemas/schema.sys.mjs",
             "browser/locales/en-US/firefox-l10n.js",
             "mobile/android/app/geckoview-prefs.js",
             "mobile/android/app/mobile.js",