Considerable efforts have been devoted to the design and fabrication of heterostructured nanocomposites using materials of different dimensions for cost-effective and high-performance water-splitting applications. However, the catalytic activity of existing semiconductor based electrocatalysts is limited by a lack of active sites and their composition. Hence, in the recent years, the semiconductor-based nanocomposites obtained more attraction due to their, cost-effective and environmental friendly nature. In this study, we propose ZnWO<inf>4</inf>/NiFe<inf>2</inf>O<inf>4</inf>/g-C<inf>3</inf>N<inf>4</inf> electrocatalyst which was prepared using a hydrothermal method. The XRD analysis of the synthesized nanocomposites reveals good crystalline quality. The FESEM analysis shows rod, spherical, and sheet-like structures for ZnWO<inf>4</inf>, NiFe<inf>2</inf>O<inf>4</inf>, and g-C<inf>3</inf>N<inf>4</inf>, respectively. The combined form of all these structures in the ternary ZnWO<inf>4</inf>/NiFe<inf>2</inf>O<inf>4</inf>/g-C<inf>3</inf>N<inf>4</inf> nanocomposites was confirmed by TEM analysis. Electrochemical water splitting analysis demonstrates that the ternary nanocomposites exhibit enhanced performance in both HER and OER. Specifically, the optimized ZnWO<inf>4</inf>/NiFe<inf>2</inf>O<inf>4</inf>/g-C<inf>3</inf>N<inf>4</inf> nanocomposites show an electrocatalytic performance enhancement of 0.2411 V vs. RHE at 10 mA/cm² during HER, with a Tafel slope of 0.158 V/dec. For OER, the ternary nanocomposites show overpotential of 0.588 V vs. RHE and a Tafel slope of 0.069 V/dec. Further, the full cell analysis of the synthesized ZnWO<inf>4</inf>/NiFe<inf>2</inf>O<inf>4</inf>/g-C<inf>3</inf>N<inf>4</inf> catalyst was fabricated as an anode and cathode and 1 M of KOH was used as electrolyte solution. The full cell analysis shoes the potential about 2.22 V at 10 mA/cm2 current density. Additionally, the electrochemical performance of the two electrode system was carried out for 10 h shows better stability which confirms that the synthesized ZnWO<inf>4</inf>/NiFe<inf>2</inf>O<inf>4</inf>/g-C<inf>3</inf>N<inf>4</inf> catalyst confirm better electrode material for water splitting application. © 2025 Elsevier B.V., All rights reserved.