For more than a century, the question of how adolescents should be taught about their emerging sexuality and sexual health has been debated in schools, within communities, and across the public sphere. Today, most efforts to provide formal sexuality education fall under two models: abstinence-only programs, which promote the benefits of restraint from sexual activity, or abstinence-plus programs, which encourage abstinence and offer lessons on safer sexual practices. The lack of consistent, compelling evidence for these widely used approaches has reinforced the need, among some leaders in the field, to reconsider the paradigm as a whole. They advocate for a shift from a narrow emphasis on reducing the risks of adolescent sexual activity toward a positive, holistic emphasis on the healthy sexual development of young people. The term "rights-based" has become increasingly linked to this concept of a more comprehensive approach to sexuality education. Discussions of a rights-based approach to sexuality education have become increasingly common in both international and U.S. contexts over the past decade. Among a small but growing group of program developers, funders, health educators, and scholars, the idea of addressing contextual factors such as gender norms, power differentials, and sexual rights within sexuality education has gained enthusiastic backing. While preliminary evidence from basic science and theoretical guidance lend support to this interest, there is little direct evidence for concluding that that this new approach is preferable to existing models. This dissertation was developed to offer a critical exploration of this new paradigm for sexuality education. In the first paper, "A Rights-Based Approach to Sexuality Education: Conceptualization, Clarification and Challenges," I present a conceptual definition for a rights-based approach to sexuality education that is consistent with and gives structure for understanding the guidelines, curricula, research, and theory that have been cited as informing the approach. Based on in-depth qualitative interviews with experts, I propose a rights-based approach as the intersection of four elements: 1) an underlying principle guiding the provision of sexuality education to youth as holders of sexual rights and responsibilities; 2) an expansion of programmatic goals beyond reducing unintended pregnancy and sexually transmitted infections; 3) a broadening of curriculum content to include issues such as gender norms, sexual orientation, sexual expression and pleasure, violence, and individual rights and responsibilities in relationships; and 4) a participatory teaching strategy that engages youth in critical thinking about their sexuality and sexual choices. In the second and third papers, I focus on one construct - adolescents' underlying attitudes about their sexual rights in relationships - of particular importance for the development, implementation, and evaluation of future rights-based sexuality education programs. In "Adolescents' Attitudes about Rights in Sexual Relationships: Measure Development and Psychometric Assessment," I describe the development of self-report survey measures that address adolescents' attitudes about their rights in steady and casual sexual relationships, and assess their psychometric properties using both classical test theory (CTT) and item response modeling (IRM) approaches. The final measures show evidence of psychometric soundness, including reliability and validity, which encourages their use in both epidemiological studies of adolescent sexual behavior and evaluations of rights-based sexuality education programs.In the third paper, "Understanding Adolescents' Attitudes about Rights in Sexual Relationships," I examine how adolescents' attitudes about their sexual relationship rights vary by demographic and behavioral characteristics, in contexts with a steady or casual sexual partner, and across the different dimensions of sexual relationship rights. Adolescents report strong support for sexual relationship rights across complex hypothetical situations, with some notable differences by individual characteristics and relationship contexts. I also investigate a theorized causal connection between attitudes about their sexual relationship rights and communication with sexual partners using a series of regression models. These analyses support a causal relationship between attitudes about rights to express sexual engagement needs and partner communication, net of plausible alternative explanations and partially mediated by comfort communicating with sexual partners. In contrast, there was no evidence to support an association between adolescents' attitudes about their rights to refuse sexual activity or rights to establish relationship autonomy and their communication with sexual partners.As a whole, this dissertation provides a critical examination of the rights-based approach to sexuality education, asking research questions not previously addressed in the literature and suggesting a number of avenues for future sexual health promotion efforts.