diff --git a/vertexai/agent_engines/templates/adk.py b/vertexai/agent_engines/templates/adk.py
index cd05dd46d3..ad93acd405 100644
--- a/vertexai/agent_engines/templates/adk.py
+++ b/vertexai/agent_engines/templates/adk.py
@@ -166,10 +166,14 @@ def __init__(self, **kwargs):
         )
         # The authorizations of the user, keyed by authorization ID.
 
-        self.user_id: Optional[str] = kwargs.get("user_id", _DEFAULT_USER_ID)
+        self.user_id: Optional[str] = kwargs.get("user_id") or kwargs.get(
+            "userId", _DEFAULT_USER_ID
+        )
         # The user ID.
 
-        self.session_id: Optional[str] = kwargs.get("session_id")
+        self.session_id: Optional[str] = kwargs.get("session_id") or kwargs.get(
+            "sessionId"
+        )
         # The session ID.
 
 
diff --git a/vertexai/preview/reasoning_engines/templates/adk.py b/vertexai/preview/reasoning_engines/templates/adk.py
index 39c799a3aa..2d39ca6cdd 100644
--- a/vertexai/preview/reasoning_engines/templates/adk.py
+++ b/vertexai/preview/reasoning_engines/templates/adk.py
@@ -180,10 +180,14 @@ def __init__(self, **kwargs):
         )
         # The authorizations of the user, keyed by authorization ID.
 
-        self.user_id: Optional[str] = kwargs.get("user_id", _DEFAULT_USER_ID)
+        self.user_id: Optional[str] = kwargs.get("user_id") or kwargs.get(
+            "userId", _DEFAULT_USER_ID
+        )
         # The user ID.
 
-        self.session_id: Optional[str] = kwargs.get("session_id")
+        self.session_id: Optional[str] = kwargs.get("session_id") or kwargs.get(
+            "sessionId"
+        )
         # The session ID.