A BSTRACT Purpose: People who suffer from knee osteoarthritis (KOA) face reduced balance, which causes increased falling and many serious complications and injuries. The purpose of the extant study was to determine the effect of proximal exercises of lower extremity on static balance parameters during quiet standing. Materials and Methods: In the present randomized controlled trial, 36 patients were divided into intervention and control groups ( n = 18 in each group). Both groups received routine physiotherapy in three sessions per week for 6 weeks, while the intervention group did proximal exercises in addition to physiotherapy routine. In the extant study, the pain intensity was measured through a visual analog scale (VAS), and individuals’ static balance parameters were measured using Biodex Balance System. All measurements were done before and after the intervention, and then statistical data analysis was performed with Statistical Package for the Social Sciences (SPSS) 24 software. Results: Intergroup comparison indicated significant progress of pain intensity, anterior–posterior (AP), and Overall balance stability in both studied groups ( P < 0.05). There was a significant increase in medial–lateral (ML) balance stability only in the intervention group ( P < 0.05). Intergroup comparison showed that there was not any significant difference between variables before the intervention ( P > 0.05). The results showed more progress in the intervention group than the control group after they received the intervention, which was significant in terms of ML balance stability ( P < 0.05). Conclusion: Adding proximal exercises to physiotherapy had more effect on ML balance stability in KOA patients; however, 6 weeks of these exercises in addition to physiotherapy had also the same effect on pain intensity, Overall, and AP balance stability.