diff --git a/api/client-server/v1/rooms.yaml b/api/client-server/v1/rooms.yaml
index bafcb98b6..ff5587a90 100644
--- a/api/client-server/v1/rooms.yaml
+++ b/api/client-server/v1/rooms.yaml
@@ -312,7 +312,7 @@ paths:
                   }
                 ],
                 "visibility": "private",
-                "private_user_data": [{
+                "account_data": [{
                     "type": "m.tag",
                     "content": {"tags": {"work": {"order": "1"}}}
                 }]
@@ -375,7 +375,7 @@ paths:
                 description: |-
                   Whether this room is visible to the ``/publicRooms`` API
                   or not."
-              private_user_data:
+              account_data:
                 type: array
                 description: |-
                   The private data that this user has attached to this room.
diff --git a/api/client-server/v1/sync.yaml b/api/client-server/v1/sync.yaml
index 8050ede39..973ccc6e3 100644
--- a/api/client-server/v1/sync.yaml
+++ b/api/client-server/v1/sync.yaml
@@ -246,7 +246,7 @@ paths:
                               }
                           ],
                           "visibility": "private",
-                          "private_user_data": [{
+                          "account_data": [{
                             "type": "m.tag",
                             "content": {"tags": {"work": {"order": "1"}}}
                           }]
@@ -336,7 +336,7 @@ paths:
                       description: |-
                         Whether this room is visible to the ``/publicRooms`` API
                         or not."
-                    private_user_data:
+                    account_data:
                       type: array
                       description: |-
                         The private data that this user has attached to
diff --git a/api/client-server/v2_alpha/sync.yaml b/api/client-server/v2_alpha/sync.yaml
index 7a597f9e4..28358f558 100644
--- a/api/client-server/v2_alpha/sync.yaml
+++ b/api/client-server/v2_alpha/sync.yaml
@@ -139,7 +139,7 @@ paths:
                             e.g. typing.
                           allOf:
                             - $ref: "definitions/event_batch.json"
-                        private_user_data:
+                        account_data:
                           title: Private User Data
                           type: object
                           description: |-
@@ -287,7 +287,7 @@ paths:
                           }
                         ]
                       },
-                      "private_user_data": {
+                      "account_data": {
                         "events": [
                           {
                             "type": "m.tags",
diff --git a/specification/modules/tags.rst b/specification/modules/tags.rst
index 681d33d71..bb467bc05 100644
--- a/specification/modules/tags.rst
+++ b/specification/modules/tags.rst
@@ -11,10 +11,10 @@ Events
 ------
 
 The tags on a room are received as single ``m.tag`` event in the
-``private_user_data`` section of a room in a v2 /sync.
+``account_data`` section of a room in a v2 /sync.
 
 The ``m.tag`` can also be received in a v1 /events response or in the
-``private_user_data`` section of a room in v1 /initialSync. ``m.tag``
+``account_data`` section of a room in v1 /initialSync. ``m.tag``
 events appearing in v1 /events will have a ``room_id`` with the room
 the tags are for.