Marshall Spring Bidwell (February 16, 1799 – October 24, 1872) was a lawyer and political figure in Upper Canada. He was born in Stockbridge, Massachusetts in 1799, the son of politician Barnabas Bidwell. His family settled in Bath in Upper Canada before the War of 1812. He studied with a law firm in Kingston and was called to the Ontario Bar in 1821. When his father was unseated in 1821 based on allegations of misappropriation of funds in Massachusetts, Bidwell presented himself as a candidate but was declared ineligible. In the April 1823 Lennox and Addington by-election, Bidwell ran against George Ham of Bath where Ham won by 13 votes.