The shooting took place in the 4500 block of South Tacoma Way near South 56 and South 58 Streets, the Tacoma Police Department said.
A large crowd of people were attending a rave hosted at a private venue when an argument broke out in an alley behind the event, and multiple shots were fired, police said.
Police initially said seven victims were injured in the shooting but later announced that an eighth victim was injured during the incident later Sunday morning. All known victims were in stable condition at that time.
It was unclear what led to the argument or how many people were involved in the altercation. No arrests were immediately made, and no suspect descriptions were released.
South Tacoma Way was expected to remain closed between South 52 and South 56 Streets for several hours as police continued to investigate the shooting.
Fox News Digital reached out to Tacoma police for more information but did not immediately hear back.