The inter-site distance effect (ISDE) has gained significant attention in heterogeneous catalysis, challenging classical models that treat adjacent nonbonded sites as isolated. Recent studies demonstrate that these sites can exhibit long-range cooperative interactions, enhancing reaction efficiencies. Fully leveraging the ISDE to overcome limitations in site reactivity requires a multidisciplinary approach and advanced techniques. This review provides a comprehensive overview of ISDE in electrocatalysis, starting with strategies for synthesizing materials with tunable inter-site distances. It examines ISDE across various catalyst models, including monometallic and heteronuclear atomic sites, active sites within clusters, and the lattice of nanocatalysts, focusing on their electronic structures, spatial geometries, and synergistic interactions. Advanced characterization and computational methods are highlighted as essential for identifying inter-site structures and distances, providing a systematic framework for understanding ISDE's role in electrocatalysis. The review also proposes best practices for studying ISDE, addressing current challenges and offering future perspectives. These insights aim to inform the design of highly efficient catalysts, enhance the understanding of catalytic mechanisms, and contribute to the development of more efficient energy conversion technologies, providing a foundation for further research into optimizing electrocatalysts.