Magnesium’s high storage capacity, with a theoretical value of about 7.6 wt.%, makes it a viable candidate for hydrogen storage. However, slow kinetics and strong thermodynamic stability lead to a rather high desorption temperature, usually above 350 °C. It has been demonstrated that nanosizing magnesium-based materials is a successful strategy for simultaneously improving the kinetic and thermodynamic characteristics of MgH₂ during hydrogen absorption and desorption. MgH₂ nanoparticles were obtained by microwave assisted synthesis. To the best of our knowledge, synthesis of MgH₂ nanoparticles by this method has not been reported. It was possible to produce MgH₂ nanoparticles smaller than 20 nm. MgO and Mg(OH)₂ were also present in the produced nanoparticles, although these compounds may enhance the processes involved in the release and absorption of hydrogen.