The current state of U.S. sexual consent education among adolescents is inadequate. Despite known benefits of receiving accurate, comprehensive information and skills regarding effective consent communication during one's teenage years, adolescents are not receiving this education from their main sources of sexual information. Thus, scholars have called for better consent programming efforts specifically geared towards adolescents. One way to successfully deliver these programs may be online, given the likeability and effectiveness of these digital methods among youth within the sexual health domain. Some steps should be taken in preparation for designing such a program: understanding adolescents' consent cognitions, as well as gaining knowledge and experience with digital health intervention design and evaluation methods. The manuscripts included in this dissertation describe my work in these areas. The first manuscript (Chapter 2) makes a valuable contribution to the sparse literature on consent cognitions among adolescents; the vast majority of consent research utilizes samples of college-aged youth. This study aimed to describe adolescents' affirmative consent attitudes and how these attitudes differ based on gender and gender role beliefs. In a sample of 226 high school students (ages 15-18) in the rural southeast, we found that affirmative consent attitudes were highest among girls and adolescents with more egalitarian gender role beliefs, compared to boys and those with less egalitarian (i.e., more traditional) gender role beliefs. Gender role beliefs was found to be a mediator of the relationship between gender and consent attitudes, signaling girls in our sample had more positive attitudes toward consent "through" having more egalitarian gender role beliefs. The second manuscript (Chapter 3) serves as a contribution to the rapidly emerging field of digital health intervention: that is, employing online programs to promote positive health outcomes and/or reduce health risks among youth. To combat barriers to dissemination of an existing, efficacious sexual health program ("HEART"), our team redeveloped the program onto an open-source platform and made updates to improve content, inclusivity, and accessibility. We evaluated the redeveloped "HEART" program among 233 high school students and gained promising results about the likeability of the program compared to the original version. This manuscript describes our three-phase process of adapting, reprogramming, and evaluating "HEART," and provides recommendations for future researchers when undergoing similar projects. The third manuscript (Chapter 4) merges the two aforementioned research areas (i.e., adolescent affirmative consent cognitions and digital sexual health intervention) to describe the development and evaluation of a digital intervention ("PACT") designed to teach adolescents information and skills surrounding affirmative sexual consent. In a national online sample of 848 youth, "PACT" was found generally acceptable, with a few notable group differences that should be explored when designing future iterations of the program. "PACT" was also efficacious at promoting affirmative consent knowledge, attitudes, and self-efficacy, with no differences by gender identity, age, sexual activity status, race/ethnicity, or sexual identity. As a whole, this dissertation adds to growing bodies of literature concerning adolescent sexual consent cognitions and the emerging field of digital health intervention. Results may be utilized in future programming efforts to promote healthy consent communication among youth, which can have positive implications for long-term outcomes related to general and sexual wellbeing. Specific recommendations for future work are outlined in Chapter 5 of this dissertation. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]