Tanning during adolescence increases skin cancer risk. Relatively few studies have examined the association between thinness attitudes and tanning attitudes and behaviors. The purpose of the current study was to examine psychosocial predictors of sunbathing and tanning bed use, specifically thin ideal internalization (TII) and motives for tanning among high school girls. Adolescent girls (N = 229) completed a 10-minute questionnaire designed to assess sunbathing and indoor tanning, TII and motives to tan (appearance, social and well-being). Hierarchical regression analyses showed that TII, β = .05, p < .05, appearance motives, β = .11, p < .01 and well-being motives, β = .11, p < .01 were all independently positively associated with sunbathing. Social motives were negatively associated with sunbathing, β = -.07, p < .05. A three-way interaction was found between the three types of motives on indoor tanning, in that appearance and well-being motives interacted to increase indoor tanning levels, especially among those who strongly endorsed social motives for tanning, β = .22, p < .05. Motives for tanning, specifically those associated with appearance and well-being, can interact to increase tanning bed use. When designing tailored interventions for skin cancer prevention in young people, researchers should consider tailoring based on motivation. Researchers and healthcare professionals who work with adolescents should attend to tanners who are motivated for both appearance and mood-related reasons, as they may be most at risk for tanning dependence and skin cancer.