A18

A18 or A-18 is a three-character acronym that may refer to:
 * A18 road (disambiguation), in several countries
 * A-18 Shrike, a Curtiss Model 76A twin radial engine monoplane service test aircraft of the mid-1930s
 * Aero A.18, a Czech fighter aircraft built in the 1920s
 * Arrows A18, a Formula One car
 * British NVC community A18 (Ranunculus fluitans community), a plant community
 * Cunninghamella A18, a fungus strain
 * A18, one of the Encyclopaedia of Chess Openings codes for the English Opening in chess
 * Subfamily A18, a rhodopsin-like receptors subfamily
 * F/A-18 Hornet, an all-weather carrier-based strike fighter designed to fill the roles of fighter aircraft and attack aircraft
 * Station number of Toei Subway Asakusa station