Witnesses told police the man grabbed onto the vehicle as it was stopped at a red light.
He reportedly held on for a couple blocks before falling off in the 9500 block of West Montgomery near Ellington in the Acres Homes area on Thursday night.
The driver kept going after the man fell, likely not realizing the man was hanging on the back, Houston police said.
A passerby noticed the man laying in the middle of the road and called 911.
He was taken to an area hospital, where he later died.
Police said they don't have a description of the vehicle that drove away.
Investigators were searching for surveillance video in the area.