diff --git a/changelog.d/19273.feature b/changelog.d/19273.feature
new file mode 100644
index 00000000000..5d8fe3d693b
--- /dev/null
+++ b/changelog.d/19273.feature
@@ -0,0 +1 @@
+Support for stable MSC4312 m.oauth UIA stage for resetting cross-signing identity with the OAuth 2.0 API.
\ No newline at end of file
diff --git a/synapse/rest/client/auth.py b/synapse/rest/client/auth.py
index 600bb51a7e7..c3644c12ce0 100644
--- a/synapse/rest/client/auth.py
+++ b/synapse/rest/client/auth.py
@@ -67,7 +67,8 @@ async def on_GET(self, request: SynapseRequest, stagetype: str) -> None:
         if not session:
             raise SynapseError(400, "No session supplied")
 
-        if stagetype == "org.matrix.cross_signing_reset":
+        # We support the unstable (`org.matrix.cross_signing_reset`) name from MSC4312 until enough clients have adopted the stable name (`m.oauth`).
+        if stagetype == "m.oauth" or stagetype == "org.matrix.cross_signing_reset":
             if self.hs.config.mas.enabled:
                 assert isinstance(self.auth, MasDelegatedAuth)
 
diff --git a/synapse/rest/client/keys.py b/synapse/rest/client/keys.py
index 5f488674b4a..502c5d495a9 100644
--- a/synapse/rest/client/keys.py
+++ b/synapse/rest/client/keys.py
@@ -560,9 +560,14 @@ async def on_POST(self, request: SynapseRequest) -> tuple[int, JsonDict]:
                         {
                             "session": "dummy",
                             "flows": [
+                                {"stages": ["m.oauth"]},
+                                # The unstable name from MSC4312 should be supported until enough clients have adopted the stable (`m.oauth`) name:
                                 {"stages": ["org.matrix.cross_signing_reset"]},
                             ],
                             "params": {
+                                "m.oauth": {
+                                    "url": url,
+                                },
                                 "org.matrix.cross_signing_reset": {
                                     "url": url,
                                 },
@@ -594,9 +599,14 @@ async def on_POST(self, request: SynapseRequest) -> tuple[int, JsonDict]:
                         {
                             "session": "dummy",
                             "flows": [
+                                {"stages": ["m.oauth"]},
+                                # The unstable name from MSC4312 should be supported until enough clients have adopted the stable (`m.oauth`) name:
                                 {"stages": ["org.matrix.cross_signing_reset"]},
                             ],
                             "params": {
+                                "m.oauth": {
+                                    "url": url,
+                                },
                                 "org.matrix.cross_signing_reset": {
                                     "url": url,
                                 },