Introduction: Lateral epicondylitis is one of the most common overuse syndrome of the extensor tendon of the forearm, characterized by pain limited ROM and affected functional activity. Symptoms mostly occur in gradual in nature. As there is paucity in literature comparing effect of eccentric exercise versus concentric exercise on Pain, Grip strength and Function in the patients of lateral epicondylitis. There was a need to conduct this study to fulfil the gap in available literature. Material & method: After taking informed written consent form from patients. They were divided into 3 groups by simple random sampling method. Group A receive Eccentric exercise addition to conventional treatment, Group B receive concentric exercise addition to conventional treatment, Group C receive conventional treatment only. Result: The data was screened for normal distribution using Kolmogorov-Simonov normality test and Shapiro-Wilk test. Wilcoxon Signed Rank test was applied to analyzed pre and post outcome measure within groups. Inter group comparison of NPRS, Grip Strength and PRTEE was done by using one-way ANOVA test. Multiple comparison between all three groups was using Post HOC analysis test. There was statistically significant difference found in NPRS, Grip strength and PRTEE score at the end of 6 weeks in between group analysis (p<0.05). while multiple comparison between groups shows that the patients undergone eccentric exercise gained significantly greater improvement in pain, grip strength and function as compared to the patient undergone concentric exercise addition to conventional and control group only. Conclusion: From the present study, it can be concluded that eccentric exercise and concentric exercise both are effective in lateral epicondylitis but eccentric exercise more effective in pain, grip strength and function in lateral epicondylitis.