Nat Jaffe (January 1, 1918 – August 5, 1945) was an American swing jazz pianist. He was married to singer Shirley Lloyd.

Jaffe lived in Berlin from 1921 to 1932, where he received classical training on piano. Upon his return to the U.S., he began playing jazz music, working with Noel Francis, the Emery Deutsch Orchestra, and as a soloist on 52nd Street. In the late 1930s he played with Jan Savitt, Joe Marsala and Billie Holiday, and recorded with Louis Armstrong (1938), Charlie Barnet (1938–39) and Jack Teagarden (1940). He led his own trio in the early 1940s and recorded in 1945 with Sarah Vaughan.

Jaffe died in 1945 as a result of complications from high blood pressure at the age of 27.