Investigators said the suspect went into Chase Bank at 12702 West Lake Houston Parkway at Summer Lake Ranch around 10:50am and passed a note to a teller, demanding money.
The teller complied and the man got away with an undisclosed amount of cash. He fled in an unknown direction.
The robber is described only as a black man between 25 and 35 years old. Police are not sure if he had a weapon. No injuries were reported.
Anyone with information that could help investigators can call the Houston Police Department or Crime Stoppers.