Johann Ulrich Mayr, was a German Baroque painter.

According to Joachim von Sandrart he was the son of the painter Susanna Mayr, whose father Johann Georg Fischer was also a painter. According to the RKD he was a pupil of Rembrandt in Amsterdam and was also a pupil of Jacob Jordaens in Antwerp. He also travelled to England and Rome and is known for etchings and genre works.