Background:Little is known about reliability and validity of instruments measuring externalizing mental health problems in immigrant ethnic minority youths.Aims:To provide an overview of studies on measurement properties of instruments measuring these problems in immigrant ethnic minority youths, their methodological quality and results.Methods:A systematic review of the literature in MEDLINE, EMbase, PsycINFO and Cochrane Library was performed. Evaluation of methodological quality of studies found was done by using the 'COSMIN-checklist'. Full text, original articles, published in English after 1990 were included. Articles had to concern the development or evaluation of the measurement properties of self-reported, parent-reported and/or teacher- or clinician-reported questionnaires assessing or screening externalizing mental health problems in immigrant ethnic minority youths. Specific results of analyses on (an) immigrant ethnic minority group had to be given.Results:Twenty-nine studies evaluating 18 instruments met our criteria. Most studies concerned instruments with known validity in Western populations, tested mainly in African Americans. Considering methodological quality, inequivalences between ethnicities were found, self-reports seemed to perform better, and administration of an instrument influenced reliability and validity.Conclusion:It seems that the majority of instruments for assessing externalizing problems in immigrant ethnic minority youths is currently not sufficiently validated. Further evaluating existing instruments is crucial to accurately assess and interpreted externalizing problems in immigrant ethnic minority youths. © 2013 Paalman et al.