BACKGROUND AND AIMS: The COVID-19 pandemic has greatly disrupted adolescents' access to sexual health services, resulting in a decline in their overall sexual well-being. This systematic review explored adolescent sexual health during the COVID-19 pandemic. METHODS: A systematic review of quantitative studies-including observational research, clinical trials, and quasi-experimental interventions-examined English-language articles published between January 2020 and February 10, 2025, sourced from databases such as PubMed, Web of Science, Scopus, and Google Scholar. Study quality was evaluated using the Newcastle-Ottawa Scale (NOS) for observational studies, Cochrane RoB 2 for clinical trials, and ROBINS-1 for quasi-experimental designs. Due to the heterogeneity of the data. RESULTS: After identifying 781 articles, 10 studies with a total sample size of 636,873 participants were included in the final systematic review. Observational studies during the COVID-19 pandemic revealed diminished access to sexual and reproductive health (SRH) services, greater dependence on informal information sources, widening health inequalities, and negative impacts on adolescent sexual behavior. Intervention studies on online SRH education demonstrate significant positive impacts across key areas: access to SRH services, safe sex practices, communication with parents about sexual health, lower acceptance of dating violence, normative beliefs regarding adolescent sexuality, HIV/STI awareness, and condom use. The findings emphasize notable improvements in communication, knowledge, and attitudes toward sexual health, driven by these targeted interventions. CONCLUSION: The COVID-19 pandemic disrupted adolescent SRH globally, reducing service access and amplifying inequities. While some behaviors (e.g., sexual activity) showed resilience, systemic gaps in education and healthcare persist. Multisectoral efforts are needed to ensure adolescents' SRH rights are upheld during crises. However, the interventional studies underscore the viability of digital, media-literate interventions in improving adolescent sexual health. TRIAL REGISTRATION: The review study was officially registered on the PROSPERO website on 02/08/2023 under the code CRD42023438631 and received approval from the jury.