Nowadays, the electric system is evolving towards a paradigm shift, with a constantly higher penetration of renewable generation, as well as the electrification of the transport and different industry sectors. This new scenario requires flexibility services to be provided to transmission and distribution grids, to allow their safe and reliable operation. From amongst the various options currently investigated, hydrogen technologies are demonstrating great potential in terms of lower energy costs for consumers/prosumers, lower emissions, and better levels of quality and security of supply. This paper provides a review of the latest state-of-the-art flexibility services that hydrogen-based technologies can provide to both DSOs and end-users. This review considers contributions from both academia and industry.