The aim of this study was to investigate how peers influence adolescent body image, and whether this influence was positive and/or negative from young peoples’ perspectives. One hundred and eleven adolescents aged 13 to 18 years from the Republic of Ireland participated in this study, in 17 focus groups. Data were analyzed using a thematic analysis approach. Findings demonstrated that peers have an overwhelming negative impact on adolescent body image, and consequently, health. Both boys and girls revealed that the peer environment is characterized by a significant pressure to conform to appearance expectations, and deviations from such expectations lead to negative peer experiences. Positive peer influences were also revealed but to a far lesser extent.