The victim told police she was stopped at a red light at 26th Street and Colorado Avenue at about 4 a.m. on Saturday when she was carjacked at gunpoint.
She was driven to the 1900 block of Stewart Street where she said she was sexually assaulted.
Police said the suspects left the woman behind.
Her car turned up later. Officers said it had been involved in a hit-and-run crash.
Anyone with information is urged to call the Santa Monica Police Department at (310) 458-8495.