Aim The acculturation process presents numerous challenges that could benefit or adversely affect immigrants' health practices. The goal of this review was to present a systematic summary of studies examining the relationship between acculturation and physical activity among immigrants and ethnic minority populations. Subjects and methods Systematic review based on 44 original studies found in electronic databases (Psychinfo/ Psyndex, Eric, Pubmed/Medline, Web of Science, SportDiscus). Studies were eligible if they were written in English, German or French, incorporated a measure of acculturation and physical activity, exercise, or sport as independent and dependent variables, and provided statistical information to judge the level of significance. The 44 studies found included 760,242 participants. A narrative synthesis was performed. Causality of effects was examined based on seven criteria: consistency, strength of associations, specificity of effects, temporality, gradient, plausibility and experimental evidence. Results Acculturation was associated with higher leisure time physical activity in 57% of all studies (even after controlling for potential confounds), independent of participants' gender, age and ethnic background. The main limitations of this review are that findings were not weighted for sample size and that publication biases might have contributed to an overestimation of the relationships. Conclusion Prevention programs aimed at stimulating participation in physical activity among immigrants should give priority to individuals with low acculturation levels and it should consider culturally specific beliefs and constraints. Additionally, prevention programs could make an effort to promote acculturation among immigrants. Future studies should use longitudinal designs which include objective assessments of physical activity and which use multidimensional and bidirectional definitions of acculturation.