Due to their tunable wavelength, high color purity, bright emission and low-cost fabrication process, perovskite nanocrystals (PeNCs) have attracted broad interest and exhibited great prospects in application areas such as solar cells, light-emitting diodes, photodetectors, and lasers. Although the fabrication of PeNCs and related optoelectronic devices has witnessed rapid development over the past several years, the poor stability of PeNCs in an external environment still remains a major drawback which severely limits the further improvement and commercialization of PeNC-based devices. Therefore, various techniques and strategies have been developed to enhance the stability of PeNCs. Among them, the encapsulation strategy has been demonstrated to be an effective way to improve the stability of PeNCs. In this review, the origin of the instability of PeNCs is first analyzed to identify the importance of encapsulation, followed by a summary and discussions on recent advances in the encapsulation of PeNCs. The potential applications of encapsulated PeNCs in various optoelectronic devices are also presented to manifest the necessity of encapsulation. Finally, the further development and outlook on encapsulation of PeNCs are analyzed in order to suggest future improvements and commercialization of PeNCs and related optoelectronic devices.