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

After leaving Fitzgerald again, 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 of jazz pianists and had influenced both his contemporaries and later generations of players.