The purpose of this study was to investigate the association of sociodemographic, psychosocial, and behavioral characteristics with screen time among school-age children in Korea. This study employed a nonexperimental, cross-sectional study design. A total of 370 children attending four elementary schools participated in the study. Self-report method was used, and instruments included screen time (time spent on TV/video/computer/video games), sleep duration, eating behavior, pros and cons of exercise, and exercise self-efficacy. According to the results, 45.7% of the children had screen time of 1-2.9 hr/day and 8.9% had 3 or more hr/day. Increased screen time showed an association with gender (boy), higher body mass index, fast food consumption, higher cons of exercise, having a working mother, and attendance at a school in an inner city area (p < 0.05). Understanding the factors associated with screen time may provide useful information in the development of health promotion programs aimed at decreasing sedentary behaviors.