Deputies responded to the call from the Riverside Drive-In, located in the 14400 block of US 90A, at about 9:30pm Monday.
The convenience store clerk said a group of four men wearing either masks or bandanas rushed into the store with one of the men demanding money and waving a gun, according to the sheriff's office.
The clerk stated that when some of the customers in the building noticed what was going on, the culprits left the store and fled the scene. They escaped with a 20-pack of beer.
Anyone with information on the incident is asked to call the Fort Bend County Sheriff's Office at 281-341-4665.