To investigate potassium's impact on mungbean yield, a field experiment was carried out in the Kut that was the Agriculture Directorate of Wasit in season 2018- 2019. This experiment compared four different potassium amounts (0, 1000, 2000 and 3000 mg.L-1), symboled K0, K1, K2 and K3, respectively. The findings of this research indicated that there were significant effects on pod length, the total number of pods per plant, seeds per pod, biological yield and grain yield, with treatment K3 achieving the highest average of 10.49 cm, 35.83 pods plant-1, 10.60 seeds pod-1, 1.430 ton ha-1, and 2.026 ton ha-1, respectively. At the same time, neither the ha harvest index nor the 100-seed weight was significantly impacted. Keywords: potassium, seed yield, biological yield, harvest index, mungbean.