Jeff Irwin (born June 19, 1977) is an American activist, progressive and politician serving as a member of the Michigan Senate. A member of the Democratic Party, he served on the from 1999 to 2010, and in the Michigan House of Representatives from 2011 to 2017. In the Michigan Senate, he represents the 18th Senate district, encompassing the cities of Ann Arbor, Saline, Ypsilanti, and Milan (portion) and the townships of Ann Arbor, Pittsfield, York, Augusta, Salem, Superior, and Ypsilanti. He replaced Rebekah Warren, who was term limited.