The main objective of this study is to construct and validate a questionnaire for measuring the job performance of accountants. The research method, based on the nature of the data, is mixed, and based on the method of data collection; it is descriptive of the correlational type. In the qualitative phase, using the nominal group technique, 30 items for the job performance of accountants were considered based on the opinions of 8 professors of accounting with executive work experience. Then, content validity of the questionnaire was assessed by the Lawshe method with a purposeful selection of 10 experienced accountants, resulting in the selection of 24 items with the highest content validity ratio for the next phase. In the quantitative phase of the study, the statistical sampling included 215 experienced accountants who were randomly selected in 2024. Examining the construct validity of the questionnaire using exploratory factor analysis showed that 22 items are placed on four factors or subscales with the interpretation of contextual, task, counterproductive, and adaptive job performance. Confirmatory factor analysis for the final confirmation of the factors indicated the confirmation of the four-factor model of accountants' job performance with 22 items. The criterion validity of the questionnaire was confirmed predictively through the positive relationship between accountants' job performance and their basic accounting skills. The reliability of the subscales and the overall scale of the job performance questionnaire in accounting was appropriate, as measured by Cronbach's alpha reliability coefficient and composite reliability. Additionally, cluster analysis indicated that accountants' job performance can be categorized into two types: normal and non-normal. Accountants with normal performance had higher mean scores in task, contextual, and adaptive subscales and a lower mean scores in the counterproductive subscale compared to the group of accountants with non-normal performance.