BackgroundStudent ratings are a popular source of course evaluations in undergraduate medical education. Data on the reliability and validity of such ratings have mostly been derived from studies unrelated to medical education. Since medical education differs considerably from other higher education settings, an analysis of factors influencing overall student ratings with a specific focus on medical education was needed.MethodsFor the purpose of this systematic review, online databases (PubMed, PsycInfo and Web of Science) were searched up to August 1st, 2013. Original research articles on the use of student ratings in course evaluations in undergraduate medical education were eligible for inclusion. Included studies considered the format of evaluation tools and assessed the association of independent and dependent (i.e., overall course ratings) variables. Inclusion and exclusion criteria were checked by two independent reviewers, and results were synthesised in a narrative review.ResultsTwenty-five studies met the inclusion criteria. Qualitative research (2 studies) indicated that overall course ratings are mainly influenced by student satisfaction with teaching and exam difficulty rather than objective determinants of high quality teaching. Quantitative research (23 studies) yielded various influencing factors related to four categories: student characteristics, exposure to teaching, satisfaction with examinations and the evaluation process itself. Female gender, greater initial interest in course content, higher exam scores and higher satisfaction with exams were associated with more positive overall course ratings.ConclusionsDue to the heterogeneity and methodological limitations of included studies, results must be interpreted with caution. Medical educators need to be aware of various influences on student ratings when developing data collection instruments and interpreting evaluation results. More research into the reliability and validity of overall course ratings as typically used in the evaluation of undergraduate medical education is warranted.Electronic supplementary materialThe online version of this article (doi:10.1186/s12909-015-0311-8) contains supplementary material, which is available to authorized users.