Introduction: The transitional phase of the college years is often associated with an enormous change in personal circumstances and the occurrence of new challenges for students and therefore might lead to an increase of perceived stress. Stress is associated with a range of adverse outcomes such as a higher risk to develop a mental disorder. Nearly one third of the students in higher education settings fulfil the criteria for at least one mental disorder. Evidence-based interventions to promote mental health are needed. This systematic review investigates into the effects of mindfulness-based interventions to reduce stress in university students. Methods: A systematic review and meta-analysis was conducted in line with the PRISMA guidelines. The systematic search was performed in December 2020 in the electronic databases PubMed, PsycINFO and Central using the following keywords: students, mindfulness, stress and RCT. Study selection process was conducted by two researchers using the Covidence tool. Risk of bias was assessed with the Cochrane RoB 2.0 tool. Meta-analytic approaches were conducted with the help of the R studio software tool. Results: 323 studies were found in the systematic search, 20 studies were additionally found, including recently published articles. In total 87 full-texts were rated for eligibility. 42 studies were included in the qualitative synthesis. A random effects meta-analysis (k=38) showed an overall small effect on the primary outcome stress. Also regarding secondary outcomes (mindfulness, anxiety and depression) a small effect size was found. Risk of bias of the majority of studies fell into the category of „some concerns“. Conclusion: Mindfulness-based interventions are effective in reducing stress in university students and therefore can make a contribution to promote mental health. Future studies should report interventions in more detail and include active control groups. Despite the heterogeneity of the interventions regarding intensity, components and delivery format this review supports the use of mindfulness for students to prevent stress.