AbstractPhotoelectrochemical (PEC) water splitting provides a promising approach to convert solar energy into hydrogen. Developing active, stable, and cost‐effective semiconductors photoelectrodes is of great significance for achieving high‐efficiency and large‐scale hydrogen production. InGaN nanowires as an important candidate have gained a great upsurge in solar water splitting due to its tunable gap, high electron mobility, large active area, and excellent chemical stability. To obtain state‐of‐the‐art InGaN nanowires‐based photoelectrodes, tremendous efforts have been devoted to enhance light absorption capacity, charge carrier dynamics, and redox activity. In this review, recent advances in InGaN nanowires as photoelectrodes for PEC water splitting are comprehensively presented, with a focus on photoelectrode optimization strategies from the aspects of surface and interface structure modulation including doping engineering, energy band engineering, heterostructure engineering, and micro‐nano engineering. The representative applications of InGaN nanowires‐based PEC tandem cell are also discussed. Finally, perspectives on remaining challenges and future development are outlined.