Abstract Background Alcohol consumption is prevalent among students, with a common tendency to overestimate peers' alcohol use, contributing to increased consumption. This misperception is evident among Flemish students. This study aimed to develop and assess a Social Norms Approach (SNA) intervention targeting Flemish students to correct misperceptions and subsequently reduce alcohol use. Methods The 'Alcoholfacts' social media campaign was implemented using a quasi-experimental design from November 2022 to March 2023. A process evaluation followed Medical Research Council guidance, and intervention effects were evaluated using baseline and post-intervention surveys. Multiple linear regression with a Difference-in-Difference approach was performed for outcome assessment, using an intention-to-treat approach. Results The process evaluation showed that 36.3% of the intervention group had seen the campaign and that most of the exposed students found the campaign credible (73.3%). However, 54.8% of the exposed ...