Thomas Day may refer to:
Sports Tom Day (rugby union) (1907–1980), Welsh rugby union player Tom Day (American football) (1935–2000), American football player Tom Day (footballer) (born 1997), English footballer
Others Thomas Day (writer) (1748–1789), British author and abolitionist Thomas Day (musician), 17th-century English choirmaster Thomas Day (pirate) (), English pirate and privateer active off New England Thomas Day (Connecticut judge) (1777–1855), American lawyer, judge, and legal scholar Thomas Day (cabinetmaker) (1801–1861), African-American furniture designer and cabinetmaker Thomas B. Day (1932–2021), American college president and physicist Thomas Fleming Day (1861–1927), British-born American sailboat designer/racer and magazine editor Thomas Cuthbert Day (1852–1935), British chemist, photo-engraver and geologist
See also Tom Dey (born 1965), American filmmaker Day (surname)