Introduction: Menstruation is the cyclic uterine bleeding experienced by most of the female of reproductive age. Dysmenorrhea literally means painful menstruation. But a more realistic and practical definition includes cases of painful menstruation of sufficient magnitude so as to incapacitate day to day activities1The present study title: A study to assess the effect of Jacobson’s Relaxation Technique on dysmenorrhea among adolescent girls in selected schools. The objectives are to identify the pain during menstruation among adolescent girls and find association of pain among adolescent girls with selected demographic variables. Material and Methods: Researcher adopted evaluative research approach. Pre-experimental method and one group pretest post-test design was used. Data collected on 60 samples. Non-probability Purposive Sampling Technique was used. Result: before intervention (41) 68.3% of the adolescent girls had moderate pain (score 5-7) and (19) 31.7% of them had severe pain (score 8-10), day 2 observation (4) 6.7% of the adolescent girls had mild pain (score 1-4) and (56) 93.3% of them had moderate pain (score 5-7). On day 3 observation (29)48.3% of the adolescent girls had mild pain (score 1-4) and (31)51.7% of them had moderate pain (score 5-7). On day 4 observations fourth, all the adolescent girls had mild pain (score 1-4). Conclusion: It was evident that the reduce dysmenorrhea among adolescent girls improved remarkably after Jacobson’s relaxation technique.