Martha Alter (8 February 1904–1976) was an American pianist and composer. She was born in New Bloomfield, Pennsylvania to parents David Boyd and Daisy Myrl Alter. She graduated from Vassar College and took a position teaching music at Connecticut College. Her papers are housed at the Vassar College Libraries.
Selected compositions include:
- O Bethlehem
- Bill George, march and song for baritone and orchestra, poem by Malcolm Cowley
- Anthony Cotnstock or A Puritan's Progress, ballet
- Groceries and Notions, drama with Gertrude Brown, book by K.K. Doughtie
- Frankenstein, Alfred Victor; Spaeth, Sigmund Gottfried; Mize, John Townsend Hinton (1951). Who is who in music.
- "History". Retrieved 5 October 2010.