The fire broke out just after 4 p.m. Tuesday in the Mill River Lane neighborhood near Tasman Drive and Cisco Way.
Crews from San Jose and Milpitas are trying to get a handle on the flames.
They have not issued an evacuation order. But they are asking homeowners to stay inside and keep their doors and windows shut to keep the smoke out.
The fire was estimated at 50-75 acres, according to the San Jose Fire Department.
As of 9 p.m., the fire was contained, but firefighters are expected to stay on the scene overnight.
No one was injured in the fire and the cause is unclear at this time.
Stay with ABC7 News for the latest details on this developing story.