Résumé : Faced with high failure rates in higher education, many institutions have introduced learning support programs to enhance student success. This study evaluates the causal impact of a peer tutoring program in the low-tuition, open-access context of French-speaking Belgian universities, using data from the Université libre de Bruxelles. Applying propensity score matching, results show that tutoring improves first-year students’ grades, by 1 to 2.5 points out of 20 and enables one third of participants to pass courses they would otherwise have failed. These findings complete existing evidence from selective systems and highlight peer tutoring as a cost-effective way to promote success.