As one of the most attractive technologies, photocatalysis arouses tremendous interest to directly harvest, convert, and store renewable solar energy for solving the energy crisis. Zinc indium sulfide (ZnIn₂S₄), a novel ternary metal chalcogenide, is highly desired owing to its non‐toxicity, low cost, and easy fabrication. However, it still suffers from some problems, including low charge‐carrier transfer rate and the ultrafast electron–hole recombination. Hence, various efficient modification methods are developed for enhancing the photocatalytic performance of ZnIn₂S₄ nanomaterials. Herein, the photocatalytic energy applications of ZnIn₂S₄‐based nanocomposites are systematically summarized, followed by a thorough discussion on the synthesis methods of ZnIn₂S₄ micro/nanostructures. Furthermore, special attention is paid to various design strategies, including dimensionality tuning, element doping, vacancy control, cocatalyst loading, and heterojunction construction. Many important energy conversion applications are also addressed, such as photocatalytic water splitting, carbon dioxide reduction, and nitrogen fixation. The influence of physicochemical properties, including structure, optical, electronic, and adsorption, on the charge dynamics for boosted photocatalytic energy applications are concluded to unravel the property–application relationship. Through reviewing the significant state‐of‐the‐art advances on this topic, the current challenges and the crucial issues of ZnIn₂S₄‐based photocatalysts are prospected.