Police say the shooting happened at the Moodswing Niteclub in the 3400 block of Kirkwood Highway in Cranston Heights in New Castle County just before 2:00 a.m.
Delaware State Police tell Action News that Philadelphia rapper Meek Mill had just finished performing inside when a fight broke out in the parking lot.
Police believe multiple gunmen fired into the crowd striking three men in their 20s and a woman in her 30s.
They were taken to Christiana Hospital for treatment with non-life threatening injuries.
State police spokesman Sgt. Paul Shavack says that when troopers arrived, about 600 to 700 people were in the parking lot trying to get away from the shooting. At least five vehicles in the parking lot were damaged by the gunfire.
Officials say police had been called to the same nightclub for a disturbance earlier that night.
The shooting remains under investigation.
Anyone with information is asked to contact Major Crimes Unit 2 at 302-834-2630.