R9 or R-9 may refer to:
Military R-9 Desna, a Soviet ICBM , a United States Navy submarine in commission from 1919 to 1931 and from 1941 to 1945
Transportation Camai Air, IATA airline code R9 (New York City Subway car) Radial Road 9 or R-9, an arterial road of Manila, Philippines Renault R9, a small French family car R9 (RER Vaud), an S-Bahn line in the canton of Vaud
Other uses HP roman9, an 8-bit character set with euro sign R9 color rendering index value for saturated red R9: Explosive when mixed with combustible material, a risk phrase in chemistry R9-Arms submachine gun, a black market submachine gun R9, a x86-64 register number 9 R-9, a fictitious starfighter from the game R-Type "R-9", a 1985 song by electronic band Cybrotron Radeon R9, graphics processing units Rohrbaugh R9, a compact pistol Ronaldo (Brazilian footballer) (born 1976), retired Brazilian footballer
See also Firestone XR-9, a 1940s American helicopter 9R (disambiguation)