N40 may refer to:
Roads N40 road (Ireland) N-40 National Highway in Pakistan Nebraska Highway 40, in the United States
Other N40 (Long Island bus) Benign prostatic hyperplasia BMW N40, an automobile engine Naughty Forty, a football hooligan firm linked to Stoke City F.C. Sky Manor Airport (New Jersey), in Hunterdon County, New Jersey, United States Toyota Hilux (N40), a Japanese pickup truck IBM RISC System/6000 N40, a laptop; see IBM RS/6000 § Type 7007