This study aimed to assess the effect of web-based reproductive health education provided to university students in Turkey on their belief in sexual myths and risky behaviours. A randomised controlled trial was conducted in a state university between March-October 2021 with 96 students. The web-based health education was developed using the ADDIE (Analysis, Design, Development, Implementation, Evaluation) model, and was delivered by means of a special platform. An intervention group of 48 students received 5 modules of education, while a control group of 48 students received none. Performance on two scales measuring information gained and risk behaviours, and sexual myths, respectively, was assessed at the beginning of the study and 5 weeks following the intervention. A statistically significant difference was observed between the two groups on both scales at the final evaluation. Additionally, a significant difference was observed in final sexual myths evaluation scores between the intervention and control groups for sexual orientation, age and sexuality, masturbation, sexual violence, sexual intercourse, and sexual satisfaction, as subdimensions of the sexual myths scale. Our findings suggest that web-based reproductive health education can be effective in reducing sexual myths and increasing knowledge about risky behaviours among university students relevant to sexual and reproductive health in young adults.