As a highly appealing technology for hydrogen generation, water electrolysis including oxygen evolution reaction (OER) at the anode and hydrogen evolution reaction (HER) at the cathode largely depends on the availability of efficient electrocatalysts. Accordingly, over the past years, much effort has been made to develop various electrocatalysts with superior performance and reduced cost. Among them, ruthenium (Ru)-based materials for OER and HER are very promising because of their prominent catalytic activity, pH-universal application, the cheapest price among the precious metal family, and so on. Herein, recent advances in this hot research field are comprehensively reviewed. A general description about water splitting is presented to understand the reaction mechanism and proposed scaling relations toward activities, and key stability issues for Ru-based materials are further given. Subsequently, various Ru-involving electrocatalysts are introduced and classified into different groups for improving or optimizing electrocatalytic properties, with a special focus on several significant bifunctional electrocatalysts along with a simulated water electrolyzer. Finally, a perspective on the existing challenges and future progress of Ru-based catalysts toward OER and HER is provided. The main aim here is to shed some light on the design and construction of emerging catalysts for energy storage and conversion technologies.