The global transition toward sustainable energy sources has prompted a paradigm shift in the field of energy storage. The separator is an important component in rechargeable batteries, which facilitates the rapid passage of ions and ensures the safety and efficiency of the electrochemical process by preventing direct contact between the anode and cathode. Traditional polyolefin‐based separators induce environmental concerns due to their nonbiodegradable nature. Biomass‐based separators derived from renewable sources such as plant fibers, agricultural waste, and biopolymers have emerged as promising alternatives to traditional polymer separators. In this review, we summarize the current state and development of biomass‐based separators for high‐performance batteries, including innovative manufacturing techniques, novel biomass materials, functionalization strategies, performance evaluation methods, and potential applications. The review also delves into the environmental impact and sustainability analysis of biomass‐based separators, offering insights into the potential of biomass as the most sustainable resource for future energy storage solutions. This review could provide a holistic understanding of the advancements and potential of biomass‐based separators, shedding light on the path toward sustainable and efficient energy storage based on biomass‐derived separators.