WJJK (104.5 FM) is a commercial radio station licensed to Noblesville, Indiana, and broadcasting to the Indianapolis metropolitan area.

WJJK has an effective radiated power (ERP) of 50,000 watts, the maximum for most stations in Indiana.

Its transmitter is located on Bulldog Road, near the athletic fields for Butler University, which once owned the station.

[3] On September 25, 1950, the station signed on the air as WAJC, with the call letters standing for Arthur Jordan College of Music.

On March 13, 2005 6pm local time WGLD became WJJK, dropping oldies and subscribing to the nationally syndicated "JACK FM" adult hits format.