diff --git a/templates/zerver/api/changelog.md b/templates/zerver/api/changelog.md
index 2a003c7bed..76bb546d9e 100644
--- a/templates/zerver/api/changelog.md
+++ b/templates/zerver/api/changelog.md
@@ -10,6 +10,13 @@ below features are supported.
 
 ## Changes in Zulip 4.0
 
+**Feature level 60**
+
+* [`PATCH /users/{user_id}`](/api/update-user): Added support for
+  changing a user's organization-level role to moderator.
+* API endpoints that return `role` values can now return `300`, the
+  encoding of the moderator role.
+
 **Feature level 59**
 
 * [`GET /users`](/api/get-users), [`GET /users/{user_id}`](/api/get-user),
diff --git a/zerver/models.py b/zerver/models.py
index bee3e5fde6..a5c11fd331 100644
--- a/zerver/models.py
+++ b/zerver/models.py
@@ -1186,6 +1186,7 @@ class UserProfile(AbstractBaseUser, PermissionsMixin):
     ROLE_TYPES = [
         ROLE_REALM_OWNER,
         ROLE_REALM_ADMINISTRATOR,
+        ROLE_MODERATOR,
         ROLE_MEMBER,
         ROLE_GUEST,
     ]
diff --git a/zerver/openapi/zulip.yaml b/zerver/openapi/zulip.yaml
index c95b6d6dfc..f9d622029a 100644
--- a/zerver/openapi/zulip.yaml
+++ b/zerver/openapi/zulip.yaml
@@ -390,6 +390,7 @@ paths:
                                           enum:
                                             - 100
                                             - 200
+                                            - 300
                                             - 400
                                             - 600
                                     - type: object
@@ -6750,6 +6751,7 @@ paths:
 
             * Organization owner: 100
             * Organization administrator: 200
+            * Organization moderator: 300
             * Member: 400
             * Guest: 600
 
@@ -6758,7 +6760,8 @@ paths:
             The owner role cannot be removed from the only organization owner.
 
             **Changes**: New in Zulip 3.0 (feature level 8), replacing the previous
-            pair of `is_admin` and `is_guest` boolean parameters.
+            pair of `is_admin` and `is_guest` boolean parameters. Organization moderator
+            role added in Zulip 4.0 (feature level 60).
           schema:
             type: integer
           example: 400
diff --git a/zerver/tests/test_users.py b/zerver/tests/test_users.py
index ee50398062..d9f21f46af 100644
--- a/zerver/tests/test_users.py
+++ b/zerver/tests/test_users.py
@@ -447,17 +447,27 @@ class PermissionTest(ZulipTestCase):
                 user_profile.is_realm_admin
                 and not user_profile.is_guest
                 and not user_profile.is_realm_owner
+                and not user_profile.is_moderator
             )
         elif role == UserProfile.ROLE_REALM_OWNER:
             return (
                 user_profile.is_realm_owner
                 and user_profile.is_realm_admin
+                and not user_profile.is_moderator
+                and not user_profile.is_guest
+            )
+        elif role == UserProfile.ROLE_MODERATOR:
+            return (
+                user_profile.is_moderator
+                and not user_profile.is_realm_owner
+                and not user_profile.is_realm_admin
                 and not user_profile.is_guest
             )
 
         if role == UserProfile.ROLE_MEMBER:
             return (
                 not user_profile.is_guest
+                and not user_profile.is_moderator
                 and not user_profile.is_realm_admin
                 and not user_profile.is_realm_owner
             )
@@ -465,6 +475,7 @@ class PermissionTest(ZulipTestCase):
         assert role == UserProfile.ROLE_GUEST
         return (
             user_profile.is_guest
+            and not user_profile.is_moderator
             and not user_profile.is_realm_admin
             and not user_profile.is_realm_owner
         )
@@ -524,6 +535,26 @@ class PermissionTest(ZulipTestCase):
         do_change_user_role(iago, UserProfile.ROLE_REALM_OWNER, acting_user=None)
         self.check_user_role_change("iago", UserProfile.ROLE_REALM_ADMINISTRATOR)
 
+    def test_change_owner_to_moderator(self) -> None:
+        iago = self.example_user("iago")
+        do_change_user_role(iago, UserProfile.ROLE_REALM_OWNER, acting_user=None)
+        self.check_user_role_change("iago", UserProfile.ROLE_MODERATOR)
+
+    def test_change_moderator_to_owner(self) -> None:
+        self.check_user_role_change("shiva", UserProfile.ROLE_REALM_OWNER)
+
+    def test_change_admin_to_moderator(self) -> None:
+        self.check_user_role_change("iago", UserProfile.ROLE_MODERATOR)
+
+    def test_change_moderator_to_admin(self) -> None:
+        self.check_user_role_change("shiva", UserProfile.ROLE_REALM_ADMINISTRATOR)
+
+    def test_change_guest_to_moderator(self) -> None:
+        self.check_user_role_change("polonius", UserProfile.ROLE_MODERATOR)
+
+    def test_change_moderator_to_guest(self) -> None:
+        self.check_user_role_change("shiva", UserProfile.ROLE_GUEST)
+
     def test_admin_user_can_change_profile_data(self) -> None:
         realm = get_realm("zulip")
         self.login("iago")