Three men entered GameStop at 552 Contra Costa Blvd. at about 8:50 p.m. One was armed with a handgun.
The men stole cash and merchandise from the store and wallets and cell phones from several customers, police said.
The suspects then fled on foot and nobody was hurt.
Investigators believe the same suspects could be responsible for several similar robberies over the last two weeks in Pleasant Hill and Concord, police said.
The suspects were described as white or Hispanic. All three were wearing dark hooded sweatshirts, ski masks and latex gloves, police said.
Anyone with information about the robberies is asked to call Pleasant Hill police at (925) 288-4600.