B15 or B-15 may refer to:

  • B15 (New York City bus), a New York City bus line
  • Ampeg Portaflex B-15 bass amplifier, introduced in 1960
  • HLA-B15, an HLA-B serotype
  • Iceberg B-15, the largest iceberg on record as of 2006
  • London Buses route B15
  • Pangamic acid, commonly referred to as B15
  • Boeing XB-15, a U.S. bomber
  • Bundesstraße 15, a German road
  • Boron-15 (B-15 or <sup>15</sup>B), an isotope of boron
  • One of the ECO codes for the Caro–Kann Defence in chess
  • Nissan Sentra chassis code, years 2000–2006
  • A nickname for Brandon Marshall, Denver Broncos wide receiver
  • LNER Class B15, a class of 20 British steam locomotives