Johann Adolf I, Duke of Saxe-Weissenfels, was a duke of Saxe-Weissenfels-Querfurt and member of the House of Wettin. He was the first son of Augustus, Duke of Saxe-Weissenfels, and his first wife, Ann

Saxe-Weissenfels was a Duchy of the Holy Roman Empire from 1656 until 1746 with its residence at Weißenfels. Ruled by a cadet branch of the Albertine House of Wettin, the duchy passed to the Electorat