It happened in the 5000 block of North Freeway around 1 a.m.
The dispute began when a man was returning to his hotel room and found someone else was parked in a space claimed by the victim, according to Houston police.
The two began arguing when the man in the car pulled out a gun and shot the victim, who died from the gunshot wound, police said. The suspect said he shot the man in self-defense, investigators said.
The victim was shot twice during the ordeal.
The suspect was being questioned by detectives, but no charges had been filed Wednesday morning.
The victim, a 31-year-old man, wasn't immediately identified, and it wasn't clear why the shooter was claiming self-defense.