HO-1 may refer to:
HO-1 or HMOX1 (Heme oxygenase 1), a human gene Hiller VZ-1 Pawnee, early military designation HO-1, a 1953 direct-lift rotor aircraft Ho-1 cannon, a Japanese World War II weapon Cherry Grove, HO-1, a site on the National Register of Historic Places in Maryland (8037) 1993 HO1, a near-Earth asteroid
See also OH-1, Ohio's 1st congressional district Kawasaki OH-1, a helicopter