It happened just before 10 p.m. on May 16 at the Denny's restaurant at 12862 Northwest Freeway.
Police said two suspects confronted customers and forced them to give them their belongings. The third suspect held an employee at gunpoint while they opened a safe.
They took off with cash and left the restaurant in a 2-door vehicle that had been waiting in the parking lot.
Investigators believe they are responsible for several other robberies in the north and northwest areas of Houston.
The suspects are described as three black men, 18 to 22 years of age, about 5 feet, 10 inches tall weighing about 170 pounds.
One suspect was seen wearing a dark gray hoodie with a white stripe on the sleeves, dark sweatpants and white Adidas sneakers. The second suspect wore a gray Chicago Bulls shirt with long black sleeves, while the third suspect was wearing all black clothing.
WATCH: Surveillance video of three men who robbed Denny's in northwest Houston
Investigators said they hope the images from the surveillance video will be enough to help them find the suspects.
"That profile should be able to be identified from someone who knows him," Houston police robbery detective Ken Nealy said.
Anyone with information in this case is urged to contact the HPD Robbery Division at 713-308-0700 or Crime Stoppers at 713-222-TIPS.
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