Mathis der Maler (Matthias the Painter) is an opera by Paul Hindemith. The libretto is also by the composer. It was first performed on 28 May 1938 in Zürich.

The opera's genesis lay in Hindemith's interest in the Reformation. The work's protagonist, Matthias Grünewald, was an actual historical figure who flourished in that era, and whose art was an inspiration to many creative figures living in the early twentieth century. Matthias's struggle for artistic expression in the repressive climate of his day is clearly a mirror of Hindemith's own life, and he began work on it as soon as the Nazis came to power.

Mathis der Maler is not often staged, despite the popularity of the Mathis der Maler symphony that Hindemith extracted from the opera. It is a complex work, and much respected by many musicians, despite its lack of widespread popularity. It has been recorded several times.