Reuben May (June 23, 1815 – September 26, 1902) was an American farmer and populist politician. He was a member of the Wisconsin State Assembly, representing the western half of Vernon County during the 1870 and 1872 sessions. He was also twice a candidate for governor of Wisconsin, running on the Greenback ticket in 1879 and the Union Labor ticket in 1890. Earlier in life, he served as a colonel in the Union Army during the American Civil War.