Michael J. Cantwell (April 1, 1837 – December 1, 1903) was an American printer and politician. Born in Ireland, Cantwell emigrated to the United States in 1849 and settled in Madison, Wisconsin. He worked as a printer for the newspaper Wisconsin Express, which later became the Wisconsin State Journal. Cantwell served in the 12th Wisconsin Volunteer Infantry Regiment during the American Civil War. He then founded the Cantwell Printing Company. He was involved with the Wisconsin Agricultural Society, the Dane County Agricultural Society, and the Wisconsin Historical Society. Cantwell served as Madison City Treasurer and on the Madison Common Council. Cantwell served in the Wisconsin State Assembly from 1885 to 1889 and was a Democrat. Cantwell died suddenly at his home in Madison, Wisconsin.