It happened around 6:30 in front of the Black Angus Restaurant on 15th Street.
Panama City police say a south Alabama man was riding his motorcycle westbound when a silver Lexus turned in front of him. He slammed into the passenger side of the Lexus.
Police say he was not wearing a helmet and was taken to the hospital with serious head injuries.
The accident is still under investigation. Panama City police say they have responded to five serious accidents involving motorcycles since Friday.