Integrating the advantages of anion vacancies and heterostructures into the catalytic materials may increase the binding affinities to intermediates, provide more active sites, and significantly promote the activity of overall water splitting. However, the successful assembly of anion vacancies and heterostructures for high-efficiency water splitting performance is still challenging. In this work, we ingeniously present the co-construction of sulfur vacancies and heterogeneous interface into Ni₃S₂/MoS₂ catalysts on nickel foam (NF). The introduction of sulfur vacancies and Ni₃S₂/MoS₂ heterostructures can significantly improve electron and ion transport, effectively improve structural stability, and enhance overall water splitting activity. The obtained V_S-Ni₃S₂/MoS₂ catalysts (V_S stands for sulfur vacancies) exhibit superior OER and HER activities, and the overpotentials for OER and HER are 180 and 71 mV at 10 mA·cm^-2, respectively. Furthermore, a low water splitting voltage of 1.46 V is required at 10 mA·cm^-2 for the V_S-Ni₃S₂/MoS₂ catalysts, which is considerably lower than most of the water splitting electrocatalysts currently reported. This work offers an effective mean for the preparation of catalysts with both anion vacancies and heterostructures for achieving high-performance alkaline overall water splitting.