Electroactive polymers (EAPs) represent a significant class of polymeric substances marked by promising features of bearing larger strains and cost effectiveness. EAPs have exhibited good performances when utilized in a range of microelectromechanical systems (MEMS) that range from biomedical to energy applications. Most of the EAPs investigated to date include actuation and sensing. A significant amount of data has been published that describes the use of EAPs in different types of MEMS; however, the utilization of these polymers in energy system is gaining considerable attention due to the current status of energy demand globally. Research has been carried out on EAPs and MEMS in isolation, in addition to the utilization of these polymers in MEMS. However, to the best of our knowledge, no work has provided a comprehensive overview of the utilization of EAPs in MEMS. In particular, there is limited literature on a comprehensive review that covers energy systems based on EAPs. Therefore, this chapter has for the first time comprehensively studies the utilization of EAPs in MEMS, specifically targeting EAPs in energy systems. This chapter mainly focuses on EAPs, their varied types for ionic and electronic polymers, MEMS, the commercially significant employments of MEMS, and finally EAP-based energy MEMS are discussed in detail. In addition, this chapter presents some significant future considerations and challenges that are associated with the utilization of EAPs in different types of MEMS.