Birch Evans Bayh III (commonly known as Evan Bayh) (pronounced /ˈbaɪ/, like "bye") (born December 26, 1955) is an American Democratic politician who has served as the junior U.S. Senator from Indiana since 1999 and earlier served as Governor of Indiana.

Bayh first held public office as the Secretary of State of Indiana, elected in 1986. He held the position for only two years before being elected Governor where he successfully advocated for state welfare reform, tax cuts, and fiscal discipline. He left his office after completing two terms and briefly took a job lecturing at Indiana University Kelley School of Business, before being elected to the U.S. Senate seat previously held by his father, Birch Bayh.

Bayh was born in Shirkieville, Indiana, to Marvella Belle Hern and Birch Bayh, who was a Senator from 1963 to 1981. Bayh attended high school at St. Albans School in Washington, DC, and went on to graduate with honors in business economics and public policy from the Indiana University Kelley School of Business in 1978, where he was a member of Phi Kappa Psi. He has a honorary Doctor of Laws degree from Golden Gate University School of Law in California.