Matthias Greitter, also Matthäus Greiter, (* about 1495 in Aichach; † December 20, 1550 in Strasbourg) was a clergyman, cantor and composer. Greitter was a clergyman and precentor at the cathedral in Strasbourg. In 1524 the Reformation prevailed there and he was faced with the choice of joining the new movement or leaving the city. He stayed, left the monastery and became assistant preacher at St. Stephen's and St. Martin's from 1528. In 1538 he took a position as a music teacher at the ''Collegium Argentinense'', the forerunner of the University of Strasbourg. Under the conditions of the Augsburg interim, he returned to the Catholic denomination in 1549 and founded a Catholic singing school. However, he died the following year presumably of the plague.

Von Greitter wrote the melody of the Kyrie (EG 178.2) and the great Gloria (EG 180.1) which are still regularly sung in the liturgy of Protestant services today. He also created about 20 other chorale melodies. He added a text to the most famous of them in 1525: '''Es sind doch selig alle, die im rechten Glauben wandeln hier''. Johannes Calvin who met the sage during his stay in Strasbourg 1538-1541introduced her to the French-speaking world. In addition, Matthias Greitter wrote 14 secular songs in four voices and a five part 'Christ is risen'. In 1544 he published a textbook of music: ''Elementale musicum juventuti accomodum''.