Purpose: Evaluating the study quality for mixed methods research is more challenging than assessing that for monomethod research because of the former’s greater complexity and procedural multiplicity—particularly, the integration of quantitative and qualitative components. Consensus on the appraisal tools of mixed methods studies is important to ensure that such studies are properly planned, conducted, reported, and reviewed. This review aims to provide a comprehensive overview of the measurement properties of appraisal tools developed to assess research quality in mixed methods research. Method: Inclusion criteria are as follows: (1) The population under investigation must be researchers. (2) Instruments must provide items, such as design, to evaluate the quality of mixed methods studies. (3) Outcomes must focus on validity (content validity, structural validity) and reliability (internal consistency). (4) Finally, the study type must be measurement property research, and hence, tool development and evaluation studies are eligible. We will search for studies published and dissertations in English and Japanese from a variety of sources, including Scopus, MEDLINE, CINAHL, PsycINFO, and dissertation ERIC, ProQuest, CiNii (Japanese), Ichushi‑Web (Japanese), and National Diet Library (Japanese). The duration of the search is not limited. All the citations will be screened and selected by two independent reviewers. Data extraction, quality assessment, and syntheses of included studies will be performed according to the Consensus-based Standards for the Selection of Health Measurement Instruments criteria. Systematic review registration number: PROSPERO registration number: CRD42021238210.