Jonathan Mayhew Wainwright II (27 July 1821 – 1 January 1863) was an officer in the United States Navy during the American Civil War. He was killed in action.
Wainwright was born in New York City to Jonathan Mayhew Wainwright I and Maria Page.
He entered the United States Navy on June 30, 1837, as a midshipman. He attended the naval school at Philadelphia in 1842-43, and became a passed midshipman, 29 June 1843. He was appointed acting Master, 10 November 1849, and commissioned Lieutenant, 17 September 1850. He was on special duty at Washington in 1861.