Osmyn Baker (May 18, 1800 – February 9, 1875) was a U.S. Representative from Massachusetts.

Baker was elected as a Whig to the Twenty-sixth Congress to fill the vacancy caused by the death of James C. Alvord.

Baker was reelected to the Twenty-seventh and Twenty-eighth Congresses and served from January 14, 1840, to March 3, 1845.

He served as chairman of the Committee on Accounts (Twenty-seventh Congress).

This article incorporates public domain material from the Biographical Directory of the United States Congress