© 2021 Hydrogen Energy Publications LLCIt reviews the available reports on the preparation and use of magnetically separable transition metal nanoparticles (TMNs) as reusable catalysts for the hydrolytic dehydrogenation of ammonia borane (AB). After a short introduction, the review starts with the papers on the employment of intrinsically magnetic TMNs as catalysts for releasing H2 gas from AB, which includes colloidal nanoparticles of intrinsically magnetic metals, TMNs in combination with materials having large surface area, and multimetallic composites containing at least one intrinsically magnetic metal together with an additional component usually acting as support or stabilizer. This is followed by a section reviewing the papers on core-shell multimetallic nanoparticles with one intrinsically magnetic metal in either core or shell used for catalyzing the hydrolysis of AB. It follows the review of papers on TMNs supported on Fe3O4, CoFe2O4, or Co3O4 forming magnetically separable catalysts for the same reaction. Then, a short section reviews the available reports on metal nanoparticles supported on carbon-coated iron. The last section gives a summary list of conclusions.