Conducting a review of systematic reviews can be challenging, especially when combining systematic quantitative, qualitative and mixed studies reviews. In this methodological discussion paper, we propose (a) a typology for categorizing various types of review of reviews and (b) an exploration of criteria pertaining to three existing critical appraisal tools (ROBIS, AMSTAR 2, and MMSR) to identify those that could be adapted for qualitative and mixed studies reviews. Further work has to be done to develop methodological guidance in conducting, interpreting, and reporting reviews of reviews that combine qualitative and quantitative data.