Introduction: Manual techniques have a special place in the treatment of osteoarthritis. However, the effects of these techniques have been investigated only on pain. Regarding this, the present study aimed to evaluate the effect of Mulligan manual technique on quadriceps and hamstrings muscles activity pattern. 
 
Materials & Methods: This quasi-experimental study was conducted on 38 volunteers with moderate knee osteoarthritis, selected through a non-randomized sampling method. The severity of osteoarthritis was determined based on the Kellgren-Lawrence grading system. In addition, the immediate effect of Mulligan manual technique on the pain and muscle amplitude in the pattern of muscle activity was investigated. The pain severity was measured using a numerical rating scale (i.e., 0-10). Furthermore, the evaluation of muscle amplitude was accomplished using surface electromyography. The data were analyzed using two-way ANOVA and paired sample t-test.
 
Findings: The results of the study showed statistically significant changes in the mean scores of the investigated variables after the implementation of Mulligan manual technique (P<0.05). However, the amplitude of all muscles did not change uniformly after the intervention; in this regard, the amplitudes of some muscles increased, while those of other muscles decreased.
 
Conclusion: As the findings indicated, treatment with Mulligan technique exerted immediate effects on the reduction of pain in patients with moderate osteoarthritis. It seems that this intervention also affected the amplitudes of quadriceps and hamstrings muscles individually in the muscle pattern.