The Michigan Senate elections of 2018 took place on November 6, 2018, alongside elections to be Michigan's governor, Class I United States Senator, Attorney General, Secretary of State as well elections for Michigan's 14 seats in the United States House of Representatives and all 110 seats in the Michigan House of Representatives; to elect the 38 members that will comprise the Michigan Senate. The Republican, Democratic and Libertarian parties chose their nominees in a partisan primary on August 7, 2018. The Working Class Party, U.S. Taxpayers Party, Green Party and Natural Law Party chose their nominees at state party conventions.

The Michigan Senate is the upper house of the Michigan Legislature. Along with the Michigan House of Representatives, it composes the state legislature, which has powers, roles and duties defined by Article IV of the Michigan Constitution, adopted in 1963. The primary purpose of the Legislature is to enact new laws and amend or repeal existing laws.