Thomas Lee Flanagan (March 16, 1930 – November 16, 2001) was an American jazz pianist and composer. He grew up in Detroit, initially influenced by such pianists as Art Tatum, Teddy Wilson, and Nat King Cole, and then by bebop musicians. Within months of moving to New York in 1956, he had recorded with Miles Davis and on Sonny Rollins' album Saxophone Colossus. Recordings under various leaders, including Giant Steps of John Coltrane, continued well into 1962, when he became vocalist Ella Fitzgerald's full-time accompanist. He worked with Fitzgerald for three years until 1965, and then in 1968 returned to be her pianist and musical director, this time for a decade.

After leaving Fitzgerald in 1978, Flanagan attracted praise for the elegance of his playing, which was principally in trio settings when under his own leadership. In his 45-year recording career, he recorded more than three dozen albums under his own name and more than 200 as a sideman. By the time of his death, he was one of the most widely admired jazz pianists and had influenced both his contemporaries and later generations of players.