diff --git a/temporalio/client/_impl.py b/temporalio/client/_impl.py
index 3986f9e82..87440491a 100644
--- a/temporalio/client/_impl.py
+++ b/temporalio/client/_impl.py
@@ -685,8 +685,9 @@ async def terminate_activity(self, input: TerminateActivityInput) -> None:
                 namespace=self._client.namespace,
                 activity_id=input.activity_id,
                 run_id=input.activity_run_id or "",
-                reason=input.reason or "",
                 identity=self._client.identity,
+                request_id=str(uuid.uuid4()),
+                reason=input.reason or "",
             ),
             retry=True,
             metadata=input.rpc_metadata,
diff --git a/tests/test_activity_operator_commands_requests.py b/tests/test_activity_operator_commands_requests.py
index f71f5566b..67e9dc78f 100644
--- a/tests/test_activity_operator_commands_requests.py
+++ b/tests/test_activity_operator_commands_requests.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import uuid
 from datetime import timedelta
 from typing import Any
 from unittest.mock import AsyncMock, Mock
@@ -27,6 +28,10 @@ def __init__(self) -> None:
             "unpause",
             temporalio.api.workflowservice.v1.UnpauseActivityExecutionResponse(),
         )
+        self.terminate_activity_execution = self._recorder(
+            "terminate",
+            temporalio.api.workflowservice.v1.TerminateActivityExecutionResponse(),
+        )
         self.update_activity_execution_options = self._recorder(
             "update",
             temporalio.api.workflowservice.v1.UpdateActivityExecutionOptionsResponse(
@@ -201,3 +206,18 @@ async def test_update_options_masks_only_changed_options(
     assert update.activity_options.start_to_close_timeout.ToTimedelta() == timedelta(
         seconds=90
     )
+
+
+async def test_terminate_activity_sends_request_id_and_reason(
+    client: Client, captured: _CapturedService
+):
+    handle = client.get_activity_handle("act-1")
+    await handle.terminate(reason="term-reason")
+
+    req = captured.requests["terminate"]
+    assert req.activity_id == "act-1"
+    assert req.reason == "term-reason"
+    assert req.identity == "test-identity"
+    assert req.namespace == "test-namespace"
+    assert req.request_id
+    assert uuid.UUID(req.request_id)