B40

B40, B-40, or B.40 may refer to:

Roads

• Autovia B-40, a Spanish motorway in Catalonia
• Bundesstraße 40, a German road

In Science

• Borospherene, B₄₀, an allotropic cage-like molecule of pure boron
• HLA-B40, an HLA-B serotype

Military

• Vietnamese designation of the RPG-2, the first rocket-propelled grenade launcher designed in the Soviet Union
• BSA B40, a 350cc British motorcycle
• Blackburn B.40, an experimental Blackburn flying boat
• Rolls-Royce B40 Engine, an inline-four petrol engine primarily used in the Austin Champ
• Unterseeboot B-40, World War I Imperial Germany Navy submarine U-boat
• YB-40 Flying Fortress, an aircraft

Other

• 40 amp, type B – a standard circuit breaker current rating
• B40 Balkan Cities Network, an intercity organization between Balkans cities
• Sicilian Defence, Encyclopaedia of Chess Openings code