IIB

IIB or IIb may refer to:
 * IIb, a diamond type
 * IIb, a type of type II supernova
 * Intergranular and Interphase Boundaries (IIB) in Materials, a series of triennial international conferences which started in Paris (France) in 1989
 * International Investment Bank, a multilateral development bank
 * "Ice Ice Baby", a hip hop song written by American rapper Vanilla Ice
 * International Patent Institute (Institut International des Brevets), an intellectual property organisation established on June 6, 1947, now defunct
 * Islamic International Brigade, an international unit of Islamist mujahideen founded in 1998
 * KBC Bank Ireland, (established in 1973 as Irish Intercontinental Bank), one of the leading non-retail banks in Ireland
 * Type II string theory (type IIB), described by type IIB supergravity in ten dimensions
 * IBM Integration Bus, an enterprise service bus software product by IBM
 * A rating in the Hong Kong motion picture rating system