The 1988 United States Senate elections were elections for the United States Senate. Held on November 8, the 33 seats of Class 1 were contested in regular elections. In spite of the Republican victory by George H. W. Bush in the presidential election, the Democrats gained a net of one seat in the Senate. Seven seats changed parties, with four incumbents being defeated. The Democratic majority in the Senate increased by one to 55–to–45.

Joseph Isadore Lieberman was an American politician and lawyer who served as a United States senator from Connecticut from 1989 to 2013. A former member of the Democratic Party, he was its nominee for vice president of the United States in the 2000 U.S. presidential election. During his final term in office, he was officially listed as an independent Democrat and caucused with and chaired committees for the Democratic Party.