N18 may refer to:
Roads N18 road (Belgium), a National Road of Belgium Route nationale 18, in France N18 road (Ireland) A18 motorway (Netherlands) N18 (South Africa) Nebraska Highway 18, in the United States
Other uses BMW N18, an automobile engine Chronic kidney disease , a submarine of the Royal Navy London Buses route N18 Nissan Almera (N18), a Japanese automobile Nitrogen-18, an isotope of nitrogen Tinak Airport, on Arno Atoll, Marshall Islands N18, a postcode district in the N postcode area