Purpose: Differences in scapular kinematics and muscle activity appear in the forward head and rounded shoulder posture (FHRSP). Thus, the aim of this study was to investigate the following effects according to different postures on scapular kinematics and muscle activity around scapular region in individuals with and without FHRSP during overhead reaching task. Methods: Thirty pain-free subjects with/without FHRSP participated in this study. All subjects were positioned into three positions: habitual head posture (HHP), self-perceived ideal head posture (SIHP) and therapist-perceived neutral head posture (TNHP). Muscle activities of upper trapezius (UT), lower trapezius (LT) and serratus anterior (SA) were measured during overhead reaching task. Results: Muscle activity of trapezius muscle (UT and LT) during HHP was significantly higher than SIHP and TNHP in FHRSP group (p<0.05), but there was no difference between SIHP and TNHP. SA also significantly increased muscle activity in HHP more than SIHP and TNHP in FHRSP group (p<0.05), but there was no significant difference between SIHP and TNHP. In Non-FHRSP group, although there was a tendency of different muscle activities among three postures, it was not statistically significant. Conclusion: This result demonstrates that muscle activity associated with overhead reaching task is increased in HHP which affects the scapular kinematics and SIHP contributes changed scapular kinematics and proper recruitment of muscle activity in FHRSP similarly to TNHP.