This paper reviews the applications of the multi-vane expanders in ORC (organic Rankine cycle) systems. The operating principle and design of the ORC systems are addressed in the introduction. Then, there is a brief review of the expanders applied in small-power and micro-power ORCs, and a discussion of the multi-vane expander design and operating principle as an introduction to a comprehensive review on the applications of the multi-vane expanders in ORC systems. The different features of the multi-vane expanders鈥攊.e., the design of the expander, its geometrical dimensions and operating conditions, durability, applied working fluid, obtained power output, and efficiency鈥攁re analyzed in this paper. This review clearly indicates that multi-vane expanders are a promising alternative to the different types of the expanders applied in ORC systems.