In this paper, state-of-the-art electrospun nanofiber-based separators for lithium-ion battery (LIB) are reviewed. Recent years, extensive efforts have been made to improve battery performances for future energy applications such as electric vehicles and energy storage systems. Separator, as a crucial component in lithium-ion battery, also gained rapid developments to achieve advanced properties. Electrospun nanofiber-based membrane is a promising candidate for separator in LIB to enhance lithium ions transportation efficiency due to its ideal features like interconnected porous structures, high porosities and large surface-to-volume ratio. In this review, we classified electrospun separator into five major types namely the monolayer separator, multilayer separator, modified separator, composite separator and gel polymer electrolyte. Each electrospun separator type was comprehensively discussed and summarized to cover the research achievements within the recent years. The outlook and future directions in this research field are also provided.