B50
B50 or B-50 may refer to:
 Bundesstraße 50, a German road
 B-50 Superfortress, an airplane
 Alcester, according to the list of postal districts in the United Kingdom
 Biodiesel#Fuel quality, standards and properties, a mixture that is half biodiesel
 B50, a Birmingham Small Arms Company 500cc motorcycle
 International Statistical Classification of Diseases and Related Health Problems (ICD-10), standard code for the type of malaria caused by Plasmodium falciparum
 Leyland Royal Tiger, a bus manufactured by Leyland Bus in the United Kingdom
 Sicilian Defence, Encyclopaedia of Chess Openings code
 Uniclass, code for the subject "History and theory of planning"
 a Vietnamese RPG-2, rocket-propelled grenade launcher
 an alternate name for human Gap-43 protein
 HLA-B50, a HLA-B serotype
 50 amp, type B – a standard circuit breaker current rating