Electric double layer capacitors (EDLCs) are a type of high-power and long-cycle energy storage device with wide operating temperature range. EDLCs have promising applications in transportation, microgrids, and the internet of things. Activated carbon, which is characterized by its high nanoporosity, high surface area, and high tap density, is the most widely applied electrode material for EDLCs. Plants, owing to the abundance, diversity, and renewability, have been considered as the most promising precursors for producing activated carbon. In this work, plant-derived activated carbon for EDLCs has been reviewed. First, the merits and operating mechanism for EDLCs have been briefly presented, and the plant-based precursors for activated carbon have been divided into four categories: agriculture & forestry plants, aquatic plants, fruit shells, and plant-derived molecules. Second, the basic requirements on activated carbon have been discussed, as well as the methods and mechanisms for preparing activated carbon. Third, the research progress of activated carbon prepared from plants has been reviewed, as well as the catalytic graphitization of the activated carbon derived from plants. Fourth, conclusions are presented, and the prospect for the promising applications in EDLCs and further research direction of plant-derived activated carbon have been delivered.