The purpose of this study was to identify the effects of shoulder stabilization exercises and stretching on shoulder height and muscle activity in young adults with rounded shoulder posture. The subjects were young adults with rounded shoulder posture, and divided into two groups: shoulder stabilization exercises and stretching exercises. The shoulder stabilization exercise group performed Thera band exercises and stretching exercises. The stretching exercise group performed stretching exercises. The groups performed the exercises for 40min, three times a week for four weeks. Shoulder height was measure by Vanier calipers and muscle activity was measured by electromyography. Shoulder height was significantly decreased in both groups after intervention, however there was no difference between groups. There was a significant difference in muscle activity between the two groups after the intervention, however there was no difference between the groups. This study suggests that shoulder stabilization exercise and stretching affect shoulder height and muscle activity.