Abstract: Limited research has been done to assess the effectiveness of Muscle Energy Technique (MET) on Temporomandibular Joint Dysfunction (TMD) patients. The present study was a randomized clinical trial that aimed to evaluate the effectiveness of MET in reducing pain and improving Maximal Mouth Opening (MMO) in patients with TMD. The sample consisted of forty participants; aged 20-30 years (mean age 25.5±2.96) diagnosed with TMD of less than three months duration were recruited. Participants were treated with MET, which includes post isometric relaxation and reciprocal inhibition, given on alternate days for 5 weeks. Before the commencement of the treatment and at the end of each week, subjects were evaluated for pain intensity using Visual Analogue Scale (VAS) and MMO by measuring the inter-incisal distance. The intra group comparison showed that there was a significant reduction of pain (p<0.05) at the end of each week as measured by the VAS. The MMO measurements showed significant improvement in range of motion (p<0.05) at the end of each week when compared to the baseline measurements. Results may have important implications for physiotherapy practice in suggesting that MET is effective in reducing pain and improving MMO in patients with TMD.