Tiny gears play a critical role in the transfer of power in smaller machinery used in the aviation, automobile, and biomedical sectors, etc. Nano-finishing tiny gears is a tough job owing to their geometry’s intricacy. Precise finishing of small gear increases its life and performance. To impart nano finishing on small gears, it is necessary to remove faults on gear’s working surfaces due to manufacturing. The faults include scratch marks, burrs, and pits. Very few finishing processes are applied to small gears due to the narrow spacing between the gear teeth. The rotational magnetorheological abrasive flow finishing process is a magnetorheological polishing fluid-based finishing process which delivers nanometer-level finishing. In the present study, this process is employed to nano finish small steel gear. This problem is addressed by developing gear workpiece fixture and synthesizes optimum polishing fluid in the finishing process. Wire electro discharge machining is used to manufacture the steel gear. After finishing the steel gear, minimum surface roughness of 34.5 nm is achieved. Maximum percentage improvement of surface roughness at involute profile of gear workpiece is obtained as 85.56%. Also, manufacturing defects are removed after the finishing process. After analyzing the finished surface, it is observed that recast layer on the ground surfaces is totally removed after the finishing procedure.