This review discusses the hydrothermal growth of ZnO nanostructures, highlighting the conditions and methods used to synthesize various ZnO nanostructures such as nanoparticles, nanowires, nanorods, nanobelts, nanoflowers, and nanocages. The hydrothermal method is favored for its simplicity and environmentally friendly conditions. ZnO is a promising material due to its unique properties, including wide bandgap, high exciton binding energy, and piezoelectric and pyroelectric properties, making it suitable for applications in optoelectronics, sensors, photodetectors, and photocatalysts. The review also covers the synthesis of ZnO nanostructures using different methods, including solution-phase and gas-phase synthesis, and discusses the role of doping in modifying the properties of ZnO nanostructures. The crystal structure of ZnO is described, and the effects of various parameters such as temperature, pH, and surfactants on the growth of ZnO nanostructures are analyzed. The review also addresses the use of microwave heating and the chemical double dip technique for the synthesis of ZnO nanostructures. Finally, the review concludes that hydrothermal synthesis is a simple and efficient method for producing ZnO nanostructures, which have a wide range of potential applications in various technological fields.This review discusses the hydrothermal growth of ZnO nanostructures, highlighting the conditions and methods used to synthesize various ZnO nanostructures such as nanoparticles, nanowires, nanorods, nanobelts, nanoflowers, and nanocages. The hydrothermal method is favored for its simplicity and environmentally friendly conditions. ZnO is a promising material due to its unique properties, including wide bandgap, high exciton binding energy, and piezoelectric and pyroelectric properties, making it suitable for applications in optoelectronics, sensors, photodetectors, and photocatalysts. The review also covers the synthesis of ZnO nanostructures using different methods, including solution-phase and gas-phase synthesis, and discusses the role of doping in modifying the properties of ZnO nanostructures. The crystal structure of ZnO is described, and the effects of various parameters such as temperature, pH, and surfactants on the growth of ZnO nanostructures are analyzed. The review also addresses the use of microwave heating and the chemical double dip technique for the synthesis of ZnO nanostructures. Finally, the review concludes that hydrothermal synthesis is a simple and efficient method for producing ZnO nanostructures, which have a wide range of potential applications in various technological fields.