IntroductionSuccessful emotion regulation (ER) is critical for psychological health. Disturbances in this ability are associated with several psychiatric disorders. There are several self-report questionnaires to assess ER. However, there are no studies synthesising the evidence on their psychometric properties. We aim to identify all available instruments addressing ER in adolescents or adults and to critically appraise, compare and summarise the quality of their psychometric properties. For this, we will use COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) criteria.Method and analysisThe search process to identify eligible studies will be conducted in April 2021 including the ProQuest, PubMed, Scopus and Web of Science databases with no restriction in terms of publication date. Eligibility criteria include peer-reviewed research articles written in English or Spanish by means of patient-reported outcome measures focused on ER among participants of 13 years or older. We will assess the quality of measures according to the COSMIN Risk of Bias Checklist. The psychometric properties will be assessed by the COSMIN updated criteria for good measurement. The available evidence will be addressed by the Grading of Recommendations, Assessment, Development and Evaluations approach. Our findings will be synthesised independently for each measure, including information on their sample, theoretical model and psychometric properties when possible.Ethics and disseminationEthical approval is not required, as this study does not involve any participants or collection of primary data. Results are expected to be published in a peer-reviewed journal in the field of youth mental health and presented at relevant meetings and conferences.PROSPERO registration numberCRD42021249498.