KSTJ may refer to:

• KSTJ (FM), a radio station (91.3 FM) licensed to serve Hartford, South Dakota, United States
• KSTJ-LP, a low-power radio station (104.3 FM) licensed to serve Sioux Falls, South Dakota
• KFRH, 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

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