Strategies for HIV prevention among infants, children, and adolescents have evolved significantly over the past 20 years. These include the global scale-up of simplified multidrug HIV regimens for pregnant women, leading to impressive reductions in new child HIV infections. However, significant gaps remain, especially in high HIV-burden sub-Saharan African countries. For example, many pregnant women living with HIV (WLHIV) are unable to access and sustain HIV testing and treatment partly due to low agency and harmful gender norms. Among pregnant WLHIV, adolescent girls face an additional layer of societal and health-system barriers in accessing care for themselves and their exposed infants. Legal and structural barriers limit access to HIV prevention-related sexual and reproductive health services among high-risk adolescents, including girls and young men who have sex with men. Key ethical issues underlying HIV prevention gaps for infants, children, and adolescents prevail. This narrative review explores these issues and highlights counter-measures for programming and policy, including gender empowerment, improving access to and appropriateness of critical health services, rights-based policy and legislation, closing research gaps, and considering the values and preferences of young people for HIV prevention and treatment services.