At least six fire departments responded to the fire at Lipstick Cabaret on Texas 146 at F.M. 646.
The club was open when the fire began.
Officials said the fire started in a storeroom wall and sent people running out of the building.
The Galveston County Sheriff's Office said it got a call from the club around 2am Saturday. The blaze went two-alarm because the smoke and fire were so intense.
Patrons inside were able to escape. There were no reports of injuries. Most of the damage was to the outside of the club.
Investigators believe the fire was caused by an electrical problem.