B5

B5, B05, B-5 may refer to:

Biology

ATC code B05 (Blood substitutes and perfusion solutions), a therapeutic subgroup of the Anatomical Therapeutic Chemical Classification System
Cytochrome b₅, ubiquitous electron transport hemoproteins
- Cytochrome b5, type A, a human microsomal cytochrome b5
HLA-B5, an HLA-B serotype
Pantothenic acid (a.k.a. vitamin B₅), a water-soluble vitamin
Procyanidin B5, a B type proanthocyanidin

Alekhine's Defence (ECO code B5), a chess opening beginning with the moves e4 Nf6
B5 (band), an R&B boy band
- B5 (album), B5's self-titled debut album
Babylon 5, an American science fiction television series

Amadeus (airline) (IATA code: B5), an airline based in Germany (1996–2004)
B5 and B5 DOHC, models of the Mazda B engine series
B-5, a variant of the Blackburn Baffin biplane
B5 platform, the series designator for Audi A4 from 1994–2001
Bundesstraße 5, German federal highway
HMS B5, a Royal Navy B-class submarine
Keystone B-5, a light bomber made for the US Army Air Corps in the early 1930s
Kinner B-5, a popular five cylinder American radial engine of the 1930s
NSB B5 (Class 5), a series of passenger carriages built by Strømmens Værksted for the Norwegian State Railways
PRR B5, an American 0-6-0 steam locomotive
SM UB-5, a German Type UB I submarine or U-boat in the German Imperial Navy