Thomas Francis Eagleton, LL.B., (born September 4, 1929) is a former U.S. Senator from Missouri. He is a member of the Democratic Party and is currently a university professor and law partner.

He served as Missouri's Attorney General and Lieutenant Governor, won a U.S. Senate seat in 1968, and sought the Vice Presidency in 1972. He was nominated for Vice President at the 1972 Democratic Party convention, with George McGovern nominated as the party's presidential candidate. His vice-presidential hopes evaporated when it was revealed shortly after the party convention that he had been hospitalized on three occasions for depression and had undergone electroshock therapy. McGovern removed Eagleton from the ticket and replaced him with Sargent Shriver. However, McGovern and Shriver lost the general election to Richard Nixon and Spiro Agnew by a wide margin that November.

He was instrumental to the Senate's passage of the Clean Air and Water Acts, and sponsored the Eagleton Amendment , which halted the bombing in Cambodia and effectively ended American involvement in the Vietnam War.

Eagleton served in public office for 30 years, the last 18 of which were in the U.S. Senate, from (1968 to 1987) where he was active in matters dealing with foreign relations, intelligence, defense, education, health care and the environment.

After three Senate terms, Eagleton returned to St. Louis, Missouri as an attorney, political commentator, and Washington University professor. He still holds the title of Professor of Public Affairs at Washington University in St. Louis. He also is a partner in the St. Louis law firm of Thompson Coburn and was a chief negotiator for a coalition of local business interests that lured the Los Angeles Rams football team to St. Louis.

The U.S. Courthouse in downtown St. Louis was named for Thomas Eagleton. He is the author of three books on politics.

He graduated from Amherst College in 1950.