Objectives: This review examines the sexual development of young men through a precarious manhood framework. The teenage and emerging adulthood years are a time of change and uncertainty for many boys and young men, heightening concerns about manhood. They are also a time when boys and young men are learning about and experimenting with sex. Sex and (hetero)sexuality are means for establishing and proving manhood, especially during a developmental period when other avenues (e.g. financial success) may be less available. Methods and Results: This paper reviews research connecting precarious notions of manhood to sexual development across three areas. First, we examine how precarious manhood encourages sexual risk-taking and objectification of sexual partners. Second, we review research connecting precarious manhood to men's sexual violence. Third, we link precarious manhood to men's derogation of gender and sexuality minority (LGBTQ+) individuals and groups. Conclusion: We end the paper by suggesting how sexual education programmes may consider a precarious manhood framework to foster healthier sexual development.