Perovskite nanocrystals (PNCs) are promising active materials because of their outstanding optoelectronic properties, which are finely tunable via size and shape. However, previous synthetic methods such as hot-injection and ligand-assisted reprecipitation require a high synthesis temperature or provide limited access to homogeneous PNCs, leading to the present lack of commercial value and real-world applications of PNCs. Here, we report a room-temperature approach to synthesize PNCs within a liquid crystalline antisolvent, enabling access to PNCs with a precisely defined size and shape and with reduced surface defects. We demonstrate that elastic strains and long-range molecular ordering of the liquid crystals play a key role in not only regulating the growth of PNCs but also promoting high surface passivation of PNCs with ligands. The approach is a simple, rapid, and room-temperature process, yet it enables access to highly homogeneous PNCs on a mass scale with substantially reduced surface defect states leading to significantly enhanced optoelectronic features. Our results provide a versatile and generalizable strategy to be broadly compatible with a range of nanomaterials and other synthetic methods such as ligand exchange and microfluidic processes.