Body dissatisfaction has become so common that most girls and women will experience it at some point in their lives. Teasing and pressure from family members have been shown to be potent influences in the development of body dissatisfaction. However, most research conducted so far focuses on teasing and pressure from mothers, and neglects siblings altogether. I examined how appearance related teasing and pressure from siblings predicted body dissatisfaction and whether sibling intimacy mediated these relationships. Using survey data from 139 female adolescents, I found that appearance related teasing and pressure from siblings significantly predicted higher levels of body dissatisfaction. I also found significant indirect effects such that sibling teasing and pressure were associated with sibling intimacy, which was associated with body dissatisfaction, although there was no evidence of full mediation. Results indicate that siblings play an important role in the development of body dissatisfaction, and in consequence, eating disorders.