Johann Julius Hecker (December 2, 1707 – June 24, 1768) was a German educator who established the first Realschule (practical high school) and Prussia's first teacher-education institution.
Hecker was born to a family of educators in Werden, then part of Prussia. As a young man, he formed an interest in theology and was drawn to pietism and the ideas of August Hermann Francke. After completing the gymnasium in Essen, he studied theology, ancient languages, medicine, and natural sciences at the University of Halle. In 1729 he became a teacher in the Francke Pädagogium, teaching every subject, including Latin, Greek, Hebrew, German, religion, history, arithmetic, botany, anatomy, physiology, and chemistry.
In 1735, Prussian king Frederick William I appointed Hecker to the position of pastor and school inspector for the Militärwaisenhaus in Potsdam, a home and school for the children and orphans of military personnel. A sermon that Hecker delivered in 1738 so impressed Frederick William that he appointed Hecker to be the first pastor of the new Trinity Church in Berlin, which was consecrated in 1739.