An experiment was conducted at Dang, Nepal in 2021 to scrutinize the effect of different doses of gibberellic acid on the growth and yield performance of oyster mushrooms (Pleurotus ostreatus). From February to April, seven different dosages of Gibberellic acid (0, 5, 10, 15, 20, 25, and 30 ppm) were tested in Completely Randomized Design (CRD), replicated 4 times with an average daily temperature of 15-28°C and relative humidity ranging from 75-90 %. The oyster mushroom cultivation was undertaken under aseptic conditions, and the growth and development of mushrooms were recorded. Results of the study revealed that the highest yield (2.55 kg/ball), number of fruiting bodies (47), and effective primordia (11), better stipe length (5.132 cm) were found in 10 ppm of GA3 application. The result suggested that GA3 at 10 ppm/packet would be the best possible concentration for the production of Oyster mushrooms.