Sasang constitutional medicine (SCM), which categorizes humans into four Sasang types according to their constitution-specific characteristics, has been identified as being useful in predicting metabolic risks and preventing non-communicable diseases (NCDs). However, no systematic review has evaluated this relationship previously. This study protocol describes a method for evaluating the association between Sasang constitution and the metabolic risk factors for NCDs. The following nine academic databases will be used as data sources for entries: Medical Literature Analysis and Retrieval System Online, Excerpta Medica database, Web of Science, and six Korean databases. All cohort, case-control, and cross-sectional studies that were published by December 2021 and could explain the association between Sasang constitution and metabolic risk factors for NCDs will be considered eligible. Two independent researchers will select studies, extract data, assess quality of studies, and qualitatively evaluate clinical evidence, subsequently. The quality assessment will be evaluated using the Newcastle-Ottawa Scale, with modifications if necessary. Quantitative data will be synthesized as a random-effects model, if applicable. The strength of clinical evidence will be performed applying the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) or GRADE-Confidence in Evidence from Reviews of Qualitative research approach. This study will contribute to helping clinicians and health authorities detect any relevant metabolic risks that patients may have, based on systematic clinical evidence. Review Registry Unique Identifying Number: reviewregistry1213.