KSTJ may refer to:

• KSTJ (FM), a radio station (91.3 FM) licensed to serve Hartford, South Dakota, United States

• KSTJ-LP, a defunct low-power radio station (104.3 FM) licensed to serve Sioux Falls, South Dakota

• KVPH, a radio station (104.3 FM) licensed to serve Las Vegas, Nevada, United States, which used the call sign KSTJ from September 1998 to October 2007

• The ICAO airport code for Rosecrans Memorial Airport in St. Joseph, Missouri, United States

• A Knight of the Venerable Order of Saint John