The comparative study in the development of peanut shelling machines is presented. Peanut shelling constitutes a significant part of peanut processing. Researchers had developed different type of peanut shelling machines, addressing the problem of shelling groundnut. Some authors modified past machines to improve efficiency and get the best possible output. This study presents the trends of these shelling machines, performance evaluation, merits, and demerits. A look at the factors affecting the performance of the shelling operation is also considered. These factors include the groundnut size, moisture content, shelling speed, sieve, concave clearance. These factors were observed based on the operational parameters, including the shelling and cleaning efficiencies, mechanical damage, and throughput capacity. The operating speed of the machines ranged from 150-300 rpm; the range of the shelling efficiency, cleaning efficiency and terminal velocity were 78-98.32%, 50.63-91.67% and 7.7-12.9 m s-1 respectively, while the mechanical damage ranged between 5.3-17.4%; the variation in the performance evaluation parameters is caused by the moisture content, variety, concave clearance, shelling speed, shelling blades, type of concave sieve. It was revealed that as shelling speed increases, the mechanical damage and shelling efficiency increase whereas as the moisture content increases (5-15% wet base), the shelling efficiency decreases, and the mechanical damage and the terminal velocity increases respectively. These factors, in different ways, influence the revenue generated by farmers.