The present research was carried out to clarify relationships between peer pressure, social networking site (SNS) addiction, and SNS-use motives in Korean adolescents. Adolescent SNS users (N = 300, 52.70% female) completed self-report measures of peer pressure, SNS addiction, and SNS-use motives. Findings indicated that adolescents reporting more peer pressure had higher levels of SNS addiction. Moreover, the relationship between peer pressure and SNS addiction was mediated by coping and social-conformity use motives. Results are discussed in terms of implications for prevention and intervention, for adolescents facing peer pressure.