[en] Highlights: • Challenges and future of 2D-transition metal dichalcogenides in the hydrogen economy. • Strategies to enhance the electrochemical hydrogen evolution of 2D-Transition metal dichalcogenides. • Developments in electrochemical hydrogen evolution of 3d- first-row transition metal dichalcogenides. • General methods to generate hydrogen from water using solar energy. • The role of 2D- transition metal dichalcogenides in enhancing photocatalytic hydrogen evolution of the catalyst. Generation of H₂ from water has emerged to be an important alternative for replacing fossil fuels. In this context, a variety of materials has been investigated as electrocatalysts or photocatalysts for the reduction of water. Of these, transition metal dichalcogenides have emerged to be effective catalysts yielding good hydrogen evolution activity. This is particularly true of photocatalysis. MoS₂ in the form of nanosheets exhibits particularly good activity in its metallic form and also in covalently linked composites with C₃N₄ and such two-dimensional (2D) materials. In this article, we present both electrochemical and photochemical catalysis by 2D-transition metal dichalcogenides in the hydrogen evolution reaction.