The study aimed to constructing a wisdom test scale among Omani university students, and to verify its psychometric properties in view of item response theory in accordance with the assumptions of the Andrich model. To achieve the objectives of the study, the researcher relied on the descriptive approach, and an experimental wisdom scale consisting of (60) items was constructed, which was applied to a sample of (719) university students: Sultan Qaboos, Al Sharqiyah, and Nizwa. The results of the study reached the following: The items of the test wisdom scale prepared in the study conformed to the assumptions of the Andrich model, which are the internal and external correspondence of the items, the correlation of the items with the scale, positional independence, and the equality of the discriminatory ability of the items. Except for six items that did not achieve the specified correlation coefficient with the scale, and three items that did not meet the assumption of differential performance of the items. These items were deleted, so that the scale in its final form consisted of (51) items. The results also indicated that the values of the reliability coefficients for the scale reached (0.99, 0.92) for the items and individuals, respectively, while the values of the separation coefficients for the scale reached (11.86, 3.42) for the items and individuals, respectively, which are high reliability and separation coefficients. As for the results of the analysis of the calibration of the scale categories according to five criteria, all results indicated that the scale is effective in grading its items. Consequently, all items of the scale were preserved, and the measurement of the categories increased at a steady pace when moving from one category to another, and the distance between the grading categories fell within the required range. In view of the previous results, the study recommended using the experiential wisdom scale, whose psychometric properties were constructed and verified in this study, in other studies and research related to experiential wisdom. Keywords: Test Wisdom, Item Response Theory, Andrich's Model