Feedback has been shown to influence the extent and rate of learning. The purpose of this research was to investigate the effects of Knowledge of Results (KR) on more accurate trials versus KR on less accurate trials on intrinsic motivation, self-confidence and anxiety changes. Participants were 60 female students with a mean age of 16 years (SD = 0.4). Participants practiced volleyball serve task in 4 session (each session included 6 blocks and each block included 6 trials) that subjects received feedback on 3 trials out of 6 trials at the completion of each 6-trial block. While one group was provided KR about the accuracy of the 3 best serves in each block, another group was given KR about the 3 poorest serves. Participants completed the intrinsic motivation inventory and the Competitive State Anxiety Inventory-2 (CSAI-2) twice as pre-test and post-test. Both groups increased their service scores across practice blocks. On the retention test without KR, which was performed seven day after the practice phase, the more accurate trials group had higher accuracy scores than the less accurate trials group. The present findings demonstrated that feedback after relatively accurate as opposed to inaccurate trials enhanced learner’s perceived competence whereas KR on less accurate trials decreased. In addition, results demonstrated that feedback after relatively accurate as opposed to inaccurate trials enhanced learner’s perceived competence whereas KR on less accurate trials decreased.