Mobile applications ("apps") designed for sexual health education have the potential to reach teens and young adults that are hard to reach through traditional platforms; however, little is known about availability of these apps and their adherence to existing guidelines. Following a search on the two major app stores, data from 2,693 apps were analyzed. Only 697 (25%) addressed sexual health, and only 15 (1%) of apps met inclusion criteria for comprehensive programs and their content was further analyzed. The content of most of these apps narrowly focused on sexually transmitted infections and pregnancy prevention and lacked information on puberty, sexual identity, and personal safety. Theoretically grounded strategies including self-efficacy and modeling behavior to strengthen behavior change efforts were largely absent. Last, we identified significant shortcomings in the literate design of these apps, including limited use of interactive features, such as videos, quizzes, or games. These findings indicate that the potential of apps as sexual health promotion tools has not yet been fully realized. We outline recommendations for developing theory- and evidence-based sexual education apps and provide suggestions for health educators on how to select relevant apps when working for youth.