Sidney Painter (September 23, 1902 – 1960) was an American medievalist at Johns Hopkins University.
Painter was born in New York City; after the Taft School he attended Yale University (AB 1925; PhD 1930). He wrote many influential books. His doctoral thesis was later published as "William Marshal: Knight-Errant, Baron, and Regent of England", and was supervised by Professor Sydney K. Mitchell at Yale University.