Teenagers in the United States hear mixed messages about sexuality from the people and institutions around them. These social norms are important for understanding teen sexuality because they shape teens sexual behaviors and because the negative sanctioning of norm violators affects teens lives. Struggles over norms and enforcement around teen sexuality are also a major cultural battleground in U.S. society today. Based on 133 in-depth interviews with college students and teen mothers and fathers, this book reveals teenagers fascinating and complicated social worlds of communication and silence, rules and inconsistencies, control and evasion, hidden behaviors and threatened reputations. The book develops theoretical tools for understanding norms and social control in ways that attend to social inequalities and emphasize conflict and change. Teen sexuality norms come in internally conflicting sets that regulate teenagers behaviors, emotions, public portrayals of behaviors, and sanctions. These norm sets and teens behaviors look very different from one community to the next. Norm enforcers-such as families, peers, schools, and communities-strategize to gain control over teens behaviors using informal social sanctions like gossip and exclusion and formal communication such as sex education, but teens strategize to keep control over their own behaviors. Most eventually seek to violate sex norms while evading negative sanctions. This book helps us understand why teen sexuality norms are sometimes effective and sometimes ineffective. It contributes to research in social psychology, adolescence, and the life course, and its findings are relevant for improving sexual and reproductive health policy.