The student, who had been shot in the chest, was rushed to a hospital with non-life threatening injuries. Investigators later determined the wound had been self-inflicted.
Kittitas County Undersheriff Clay Myers said it appears the shooting happened at about 10:30 a.m. in a residential neighborhood east of the school grounds.
School staff immediately initiated lockdown procedures and called local law enforcement agencies, which responded and secured and searched both the Secondary School and the nearby Elementary School to verify that no further threats were present.
The school lockdown was later lifted, and normal after-school activities will resume this evening, said Principal Chris Brower. School will be on regular schedule on Friday.