Sexual health literacy (SHL) is crucial for adolescent health. Measurement consistency aids in comparing studies and informing interventions. This systematic review identifies available self-report outcome measurement instruments (OMI) assessing SHL in adolescents, explores the aspects of SHL they cover, and assess their psychometric quality. Guided by the COSMIN guidelines, a systematic search of 9 databases was conducted, focusing on studies between 2002 and 18 April 2023. Inclusion criteria encompassed studies developing and validating OMIs assessing SHL in adolescents aged 10–19 years, with a focus on self-report OMIs developed since 2002—the year the World Health Organization (WHO, 2006) defined sexual health as it is defined today (WHO, 2006). A narrative synthesis assessed the conceptual fit of identified instruments with SHL dimensions. The quality of the development studies was evaluated using COSMIN criteria. The review was preregistered in PROSPERO (ID: CRD42022303682). Out of 18,637 records, 83 studies examining 68 different OMIs were included. OMIs varied in their coverage of SHL dimensions, with appraisal and application of sexual health information most frequently addressed. The quality of OMI development was generally inadequate or doubtful, with deficiencies noted in involvement of the target population and piloting processes. Findings underscore the need for standardized, well-developed OMIs to measure SHL in adolescents. Despite availability, OMIs’ quality and alignment with SHL are insufficient. There is a clear need for improvement in OMI development processes, including greater involvement of the target population and more rigorous piloting procedures. Additionally, developing a comprehensive SHL measure will enhance comparability and promote adolescent sexual health understanding and interventions.
