The violence erupted around 2 a.m. ET Sunday after a large fight broke out, Orlando Police Chief Eric D. Smith said.
An unidentified assailant pulled out a handgun and fired into the crowd, injuring seven people.
All seven victims were taken to a nearby hospital, where they were listed in stable condition, Smith said.
Authorities do not immediately have a description of the shooter.
Both the Gun Violence Archive and CNN define a mass shooting as one in which at least four people are shot, excluding the shooter.