The 1976 United States Senate election in Michigan took place on November 2, 1976. Incumbent Democratic U.S. Senator Philip Hart decided to retire instead of seeking a fourth term because he had terminal cancer. Republican turned Democrat Representative Donald Riegle won the open seat, keeping it in Democrats' hands despite Gerald Ford's victory in the concurrent presidential election.
Incumbent Senator Hart died of melanoma on December 26, and Riegle was appointed to finish the remaining days of his final term in office, giving him seniority over his freshman colleagues.