The present study targeted Japanese female adolescents and examined the relationship between two specific ER strategies (reappraisal and suppression) and school adjustment, with social support as a mediating variable. Our findings suggest that reappraisal is an effective strategy that promotes receiving social support and consequently enhances school adjustment. Suppression, on the other hand, has neither favorable nor harmful impacts on school adjustment, but may, in the long run, result in poorer adjustment by impairing social relationships among adolescent girls.