WTMJ may refer to:
- WTMJ-TV, a television station (channel 4 analog/28 digital) licensed to Milwaukee, Wisconsin, United States
- WTMJ (AM), a radio station (620 AM) licensed to Milwaukee, Wisconsin, United States
- WLWK-FM, a radio station (94.5 FM) licensed to Milwaukee, Wisconsin, United States, which formerly used the call sign WTMJ-FM
- WLUM-FM, a radio station (102.1 FM) licensed to Milwaukee, Wisconsin, United States, which used the call sign WTMJ-FM until 1950