The development of advanced energy conversion and storage technologies is essential for optimizing the integration of sustainable energy resources into current-running power grid systems. As one of the key energy-storage carriers, hydrogen (H2) possesses ultrahigh gravimetric energy density, ecofriendly character, and high renewability during its production and combustion processes. The development of green electricity powered H2 production techniques is a highly competitive solution to meet current energy and environmental challenges. Among different industrial approaches for H2 production, platinum-supported electrocatalytic water splitting via hydrogen evolution reaction (HER) is a rather mature technique. However, it has been increasingly demanded to explore highperformance, earth-abundant, and cost-effective HER electrocatalysts that can further improve energy efficiency and bring down the production cost. Thanks to their abundant active edge sites, superior electrocatalytic activity, good stability, and low cost, two-dimensional (2D) transition metal dichalcogenide (TMD) based electrocatalysts have been recognized as promising alternatives. This chapter deals with recent advances in the exploration of 2D TMD-based HER catalysts for water-splitting hydrogen generation. We present a brief introduction to the current main techniques for H2 production and the recent development of HER electrocatalysts. The introduction is followed by the description of the basic process of water electrolysis, general working principles of HER electrocatalysts, and main synthetic methods of 2D TMD-based materials.We then highlight some representative 2D TMD materials used as HER electrocatalysts and conclude with the remarks and outlook of the relevant research lines.