InP quantum dots (QDs) are promising heavy-metal-free materials for next-generation solid-state lighting, covering from visible to near-infrared (NIR) range. Compared with the rapid development of visible InP QDs, the synthesis of high-performance NIR InP QDs remains to be solved. In this work, we report a simple one-pot synthesis of NIR InP QDs by controlling the Cu doping and designing a multishell structure. By replacing the conventional highly reactive phosphorus precursor with a slightly less reactive and low-cost ammonia phosphorus precursor, the nucleation process is effectively regulated for efficient Cu doping. In addition, the epitaxial growth of the ZnSe/ZnS shell further improves the stability and optical properties of InP QDs. Therefore, the synthesized Cu:InP/ZnSe/ZnS QDs have a photoluminescence quantum yield of 70% centered at 833 nm. The NIR InP light-emitting diodes exhibit a maximum radiance of 3.1 W·sr⁻¹·m⁻² and a peak external quantum efficiency of 2.71% centered at 864 nm.