Hydrogen storage for transportation applications requires high volumetric and gravimetric storage capacity. B–N compounds are well suited as storage materials due to their light weight and propensity for bearing multiple protic (N–H) and hydridic (B–H) hydrogens. This critical review briefly covers the various methods of hydrogen storage, and then concentrates on chemical hydrogen storage using B–N compounds. The simplest B–N compound, ammonia borane (H₃NBH₃), which has a potential 19.6 wt% hydrogen storage capacity, will be emphasised (127 references).