David Clayton-Thomas (born David Henry Thomsett, 13 September 1941) is a Grammy Award-winning Canadian musician, singer, and songwriter, best known as the lead vocalist of the American band Blood, Sweat & Tears. Clayton-Thomas has been inducted into the Canadian Music Hall of Fame and in 2007 his jazz/rock composition "Spinning Wheel" was enshrined in the Canadian Songwriter's Hall of Fame. In 2010, Clayton-Thomas received his star on Canada's Walk of Fame.

Clayton-Thomas began his music career in the early 1960s, working the clubs on Toronto's Yonge Street, where he discovered his love of singing and playing the blues. Before moving to New York City in 1967, Clayton-Thomas fronted a couple of local bands, first The Shays and then The Bossmen, one of the earliest rock bands with significant jazz influences. But the real success came only a few difficult years later when he joined Blood, Sweat & Tears.