The 1986 United States Senate election in Missouri was held on November 4, 1986. Incumbent Democratic Senator Thomas Eagleton decided to retire instead of seeking a fourth term. Republican former Governor Kit Bond won the open seat. Kit Bond was the first Republican to win the Class 3 Senate seat in Missouri since 1944, and the first Republican to get over 50% of the vote for this seat since 1920. This was the only seat that Republicans flipped in 1986.