[Purpose] The present study was performed to investigate whether forward head posture (FHP) affects muscle activity. [Subjects and Methods] Twenty subjects attending Y university in Gyeongsangnam-do, Republic of Korea. They were divided into two groups according to craniovertebral angle: a control group (n=10) and a FHP group (n=10). Electromyography electrodes were attached to the upper fibers of the trapezius, middle fibers of the trapezius, the splenii (splenius capitis and splenius cervicis), and the sternocleidomastoid (SCM) muscle to measure muscle activity during the neck protraction and retraction. [Results] EMG activities of the middle trapezius, splenii, and SCM muscle showed significant differences between the control group and the FHP group. However, the EMG activity of the upper trapezius muscle showed no significant difference between the two groups during neck protraction and retraction. [Conclusion] The results suggest that FHP alters the muscle activity in neck protraction and retraction.