The aim of this study is to investigate the mediation effect of reactions to teasing on the relationship between teasing and in adolescentmental health. A standardized, pilot-tested survey was administered to a stratified, multistage, random sample (n = 1579) of Taiwanese 7-9 graders in 2007. Structural equation modeling (SEM) was used to investigate the mediation effect of reactions to teasing and their impact on mental health. Results of factor analysis indicated that reactions to teasing could be divided into feel-threatened reactions and non-defensive reactions. The results of SEM indicated that reactions to teasing mediated the relationship between experiences of being teased and mental health. Adolescents who had feel-threatened reactions to teasing are more likely to report poor mental health.