The aim of this study is to investigate the effect of twelve-week service training on self-confidence in racquet sports. The universe of the study consists of the secondary schools in the province of Van, and the sample consists of 60 students from 10 to 14 years of age in Hasan Ali Yücel Secondary School in Van and TOBB Secondary School. Self-Concept Scale developed by "Piers-Harris" (1984) and adapted to Turkish Öner (1996) to evaluate their self-confidence before and after the study. In evaluating the performances, Dewitt-Dugan Tennis Test, Target Service Test, French-Stalter Badminton Service tests were applied. After the normality test was done, Independent-Sample T test was used for binary independent variables and paired-sample T test for dependent groups. The effect of self-confidence on the hit was tested by regression analysis. Significance level (p ˂ 0.05) was evaluated. When the finding of the study were examined, no change was observed between pre-test and post-test of the control group, while significant changes were observed between pre-test and post-test of the experimental group. As a result of this study, that can be said that 12-week service training positively affect self-confidence of rackets sports athletes.