BackgroundPrinciples of ethics are among the pillars of the teaching-learning system. Evaluation of educators’ adherence to principles of ethics in virtual education requires the use of reliable instruments. This study was carried out to develop and test the psychometric properties of a questionnaire for assessment of medical science educators’ adherence to principles of ethics in virtual education.MethodsThis is an exploratory sequential mixed methods study conducted in two parts. In the first stage (the qualitative phase), we used conventional content analysis to establish the concept of ethical principles in virtual education. Thus, 21 semi-structured, in-depth interviews were conducted with 21 medical science professors on a face-to-face basis from March 2022 to November 2022. Subsequently, we developed the items of the questionnaire based on a review of literature and semi-structured in-depth interviews. In the second stage (the quantitative phase), psychometric features of the questionnaire were evaluated using COSMIN criteria (face validity, content validity, construct validity and internal consistency).ResultsConstruct validity was surveyed with exploratory and confirmatory factor analysis via completing the questionnaire by 300 medical science professors, who were selected using convenience sampling. The results of exploratory factor analysis yielded a factor loading of the 20 items of the questionnaire to range between 0.79 and 0.98, all the values being significant. The three factors of adherence to the principles of copyright, adherence to educational principles, and justice in evaluation, which were addressed by the instrument, were verified by satisfactory values. The confirmatory factor analysis (CFA) fitted the data well (χ2/df = 13), RMSEA = 0.01, CFI = 0.96, NFI = 0.97, and TLI = 0.99. The total interclass correlation (ICC) of the questionnaire was estimated to be 0.90. Moreover, the reliability of the instrument measured in terms of internal consistency was estimated 0.98.ConclusionThe findings of the study indicated that the questionnaire we developed for evaluation of adherence to ethical principles of in virtual education was valid and reliable enough. Therefore, the managers in the education system can employ this instrument to assess medical science educators’ adherence to principles of ethics in virtual education.