Hydrogen storage remains a largely unsolved problem facing the green energy revolution. One approach is physisorption on very high surface area materials incorporating metal atoms. Boron nitride nanotubes (BNNTs) are a promising material for this application as their behaviour is largely independent of the nanoscopic physical features providing a greater degree of tolerance in their synthesis. Aluminum doping has been shown to be a promising approach for carbon nanotubes but has been underexplored for BNNTs. Using first principles density functional theory, the energetics, electronics and structural impacts of aluminum adsorption to both zigzag and armchair polymorphs of BNNTs was investigated along with their potential capacity to adsorb hydrogen. The fine atomic structural and electronic details of these interactions is discussed. We predicted that in an ideal situation, highly aluminum-doped armchair and zigzag BNNTs could adsorb up to 9.4 and 8.6 wt percent hydrogen, well above the United States Department of Energy targets marking these as promising materials worthy of further study. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.