Exploring bifunctional electrocatalysts with high efficiency, low cost, and durability is of great importance for water electrolysis but still remains a great challenge and needs to be thoroughly studied. In this work, rose-like, ruthenium-doped cobalt nitride nanoflowers grown in situ on Ti₃C₂T_x MXene are synthesized through a simple oil bath method followed by nitridation treatment under an NH₃ atmosphere. Benefiting from good conductivity and an optimized electronic structure, the resultant Ru–CoN/Ti₃C₂T_x MXene exhibits remarkable and stable bifunctional electrocatalytic activities towards both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in 1.0 M KOH solution. More importantly, a two-electrode electrolyzer constructed with the Ru–CoN/Ti₃C₂T_x MXene only needs a low cell voltage of 1.52 V to deliver a current density of 10 mA cm⁻², outperforming the benchmark RuO₂‖Pt/C couple and most recently reported representative bifunctional electrocatalysts. This work provides a new strategy for the rational design and fabrication of efficient and nonprecious catalysts for water electrocatalysis and other electrochemical energy systems.