Officers say they responded to the 1100 block of Harford Road around 4:05 p.m. Sunday for a shooting.
When police arrived, they found a 23-year-old man suffering from a gun wound to the back of the head.
The victim was transported to a hospital for treatment.
Police have not yet identified a suspect in the incident.
Anyone with information is urged to contact Citywide Shooting detectives, at ?410-396-2221.