Abstract Background Sexual ill-health causes a high health burden. There is, therefore, a need for more effective sexual health promotion interventions. Previous research has focused on preventive sexual health interventions and the limited evidence concerning school-based sexual health promotion interventions has not been synthesized. Hence, this study aimed to systematically review the current evidence on the effects of sexual health promotion interventions conducted in European schools. Methods A systematic review based on the JBI and PRISMA standards was performed, encompassing searches in seven databases to identify sexual health promotion interventions conducted in European schools between 2012 and 2022. Data coding was performed according to a predetermined protocol and a narrative synthesis of the included studies was performed, highlighting the collective results. Results The review included 17 records, reporting 16 individual studies conducted in 7 European countries. Of the 16 included studies, 13 had a quantitative research design, and three had a qualitative design. All qualitative studies described positive effects as experienced by the participants, and ten of the quantitative studies showed statistically significant positive effects on at least one of the outcomes of interest. Conclusions The findings indicate good evidence for the effectiveness of interventions with a health promotion approach, underscoring the importance of sexual health resources such as respect, communication skills, and attitudes. Most sexual health promotion intervention studies have focused on sexual health resource outcomes connected to attitudes and skills, whereas, e.g., sexual health literacy is less studied and can be recommended to be included in future research. Key messages • The synthesized evidence sheds light on the lack of evaluated interventions employing holistic and positive, resource-focused sexual health promotion interventions targeting European adolescents. • The included school-based sexual health promotion studies, although limited in number, show evidence of promising effects on sexual health outcomes among participants.