Published research suggests that cultural practices and institutional structures influence adolescent girls' engagement and achievement in school. This study was an attempt to further investigate that claim by describing the perceptions of agency held by four adolescent girls in high school. Members of the same English class, the girls volunteered to participate in three lunchtime meetings to discuss Evelyn Coleman's (2001) Born In Sin. Analysis of classroom observations, transcripts of audio recordings of the book discussions, and individual interviews yielded a more precise definition of agency than those used in previous research, including a view of agency as dialogic. In addition, four major themes describe these girls' agentic moves: (1) a temporal orientation, which connects the past, present, and future; (2) responsibility for positive and negative events; (3) strategic decision making; (4) negotiating with people in power. Implications of this study inform both teaching decisions and future research related to adolescent girls.