Jan III

Jan III may refer to:


 * Jan III van Diest (died 1340)
 * Jan III of Oświęcim (1366–1405)
 * Jan III van Montfoort (c. 1448 – 1522)
 * John III, Lord of Bergen op Zoom (1452–1532)
 * John III Sobieski (1629–1696)
 * Jan III Sobieski High School in Kraków