BACKGROUND: A proper measurement instrument is selected based on the suggested use of the instrument, the target concept of measurement, and features of measurement (e.g. internal consistency, reproducibility, content and construct validity, responsiveness, and interpretability). Concerning the design and features of measurement, there are not any adequately specific standards for instrumentation to measure oral health literacy (OHL). The present study proposes a protocol that attempts to fill this gap by introducing the psychometrics of a standard questionnaire which measures OHL. MATERIALS AND METHODS: The present research employs a methodological design and is carried out in Tehran, with data collected through interviews that are held face to face. The data collection procedure involves a review of the related literature, cognitive interviews, fuzzy Delphi Method, and focal groups with participants with OHL work experience for item generation. The target participants of this research are the Iranian adult population and experts working professionally in different health domains. For qualitative data analysis, the content analysis strategy and in the instrument Psychometrics COSMIN checklist will use. CONCLUSIONS: Achievement of the present research will be used to evaluate the capability of the Iranian adult population in searching, processing, and deciding on healthcare services. This instrument will focus on evaluating both clinical and nonclinical settings. The present research can vastly improve our knowledge of the state of OHL in the Iranian adult population.