Udy or UDY may refer to:
People Dan Udy (1874–1935), New Zealand rugby union player. Giles Udy (born 1956), English writer and historian of the Soviet Gulag system. Gloster Udy (1918–2003), Australian Uniting Church minister and author. Hart Udy (1857–1934), New Zealand rugby union player. James Udy (1920–2003), Australian Uniting Church minister. Marvin J. Udy (1892-1959), American engineer.
Other Udy (river), a river in Belgorod Oblast (Russia) and Kharkiv Oblast (Ukraine). Udy (village), a village in Kharkiv Oblast, Ukraine.