The blaze is burning in a part of the base called the Naval Weapons Station in the northeast part of the base near Fallbrook, a base spokesman told Fox 5 News. It broke out at about 9:45 a.m.
As of 11 a.m., the fire had spread to about 100 acres and was being blown toward the west by strong winds.
The Naval Weapons Station and the De Luz family housing area are being evacuated. The Mary Fay Elementary School on campus has also been evacuated.
This story will be updated as more information becomes available.