Harry Ruby (October 29, 1895 – February 23, 1974) was an American songwriter and screenwriter.

Born in New York, Ruby failed in his early ambition to become a professional baseball player. Touring the vaudeville circuit as a pianist with the Bootblack Trio and the Messenger Boys Trio he met his long-time partner Bert Kalmar. Together, Ruby and Kalmar formed a successful songwriting team until the latter's death in 1947.

Harry Ruby died in Woodland Hills, California.

Music by Ruby can be heard in the films:

• Animal Crackers (1930)
• Horse Feathers (1932)
• Duck Soup (1933)
• Bright Lights (1935)
• Walking on Air (1936)

Ruby also screenwrote such works as:

• The Kid from Spain (1932)
• Horse Feathers (1932)
• Duck Soup (1933)
• Bright Lights (1935)
• A Night at the Opera (1935)
• Walking on Air (1936)
• The Life of the Party (1937)
• Lovely to Look at (1952)