Mary Valentine (born December 30, 1946) is a politician from the U.S. state of Michigan. She is a Democrat and former member of the Michigan State House of Representatives. She represented the 91st State House District, which includes most of Muskegon County, except for the city of Muskegon and surrounding areas. It also includes a small portion of Ottawa County. In 2010 she ran for the state senate, but was defeated in a landslide by her Republican opponent.