In recent years, a new and promising polymer processing technology known as water‐assisted injection molding (WAIM) has attracted attention not only for academic reasons but also for its industrial applications. WAIM technology provides a new way to fabricate hollow or other complicated products due to its faster cycling time and light weight. This paper aims to give an overview of the basic principles and applications of WAIM as well as the current research status in academia. The origin and development of WAIM technology are first described and then, their advantages and applications are given. This review focuses on the experimental trends of WAIM such as computer simulation, the effect of processing parameters on the WAIM samples, and the morphology as well as related WAIM–molded composites and polymer blends' work. This review is intended to provide an overview of the current research status in water‐assisted injection molding (WAIM). The main objective is to review the current research of WAIM such as computer simulation, the effect of processing parameters on the water penetration length and residual wall thickness, morphology, and orientation as well as related WAIM–molded composites and polymer blends.