Maurice Lenz (March 23, 1890 – January 4, 1974) was a pioneer in the field of radiation therapy. Born in Kovno, Russian Empire (now Kaunas, Lithuania), Lenz studied at New York University and Bellevue Medical College, and received his medical degree from Columbia University College of Physicians and Surgeons in 1913. He was a professor of radiation oncology at the Columbia University College of Physicians and Surgeons, a past president of the American Radium Society and held many other clinical and administrative roles throughout a long career in medicine.