A37, A 37, A.37 or A-37 may refer to:

• A37 road (England), a road connecting Dorchester, Dorset and Bristol
• A37 road (South) (Northern Ireland), a short road connecting the N53 road in the Republic of Ireland, which is the main road between Castleblaney and Dundalk
• A37 road (North) (Northern Ireland), a road connecting Coleraine and Limavady
• A 37 motorway (Germany), a road connecting the borough of Hannover-Buchholz and Burgdorf via Altwarmbüchen and the Hanover fairground to the A7
• A37 road (Isle of Man), or Marine Drive Road
• A37 motorway (Netherlands), a road connecting Hoogeveen with Emmen and the German border near Zwartemeer
• A-37 (Michigan county highway), a road in Michigan connecting Allegan and Hudsonville

• A37, one of the English Opening codes in the Encyclopaedia of Chess Openings
• Cessna A-37 Dragonfly, a light attack jet aircraft
• Saunders Roe A.37 Shrimp, a 1939 British two-seat four-engined experimental flying boat