This study used a feminist developmental framework to test the hypothesis that internalizing conventional ideas about femininity in two domains--inauthenticity in relationships and body objectification--is associated with diminished sexual health among adolescent girls. In this study, sexual health was conceptualized as feelings of sexual self-efficacy (i.e., a girl's conviction that she can act upon her own sexual needs in a relationship) and protection behavior (i.e., from both STIs and unwanted pregnancy). A total of 116 girls (aged 16-19) completed measures of femininity ideology, sexual self-efficacy, sexual experiences, and protection behavior. Results revealed that inauthenticity in relationships and body objectification were associated with poorer sexual self-efficacy and sexual self-efficacy, in turn, predicted less sexual experience and less use of protection. Further, the two components of femininity ideology were associated with different forms of protection. The importance of a feminist developmental framework for identifying and understanding salient dimensions of sexual health for female adolescents is discussed.