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

Entertainment

 * 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
 * The Be Five, a band formed by castmembers of Babylon 5

Transport

 * 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, the manufacturer's model number for the Blackburn Baffin biplane
 * B5 platform, the series designator for Audi A4 from 1994–2001
 * Bundesstraße 5, a 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
 * B5 biodiesel
 * LNER Class B5, a British class of steam locomotives

Other

 * Baseball5, the five-a-side version of baseball
 * B5 Championships, a 2001 fighting game tournament
 * %B5, the percent-encoding for the letter μ
 * B5, a paper size of the B series defined in ISO 216
 * B5, a category of stellar classification
 * Bensen B-5, a small rotor kite
 * Border Five