Recently, psychometricians and researchers have voiced their concern over the exploration of language test items in light of Messick's validation framework. Validity has been central to test development and use; however, it has not received due attention in language tests having grave consequences for test takers. The present study sought to examine the validity of the University of Tehran English language proficiency test (UTEPT) using 6 aspects of Messick's validation framework (i.e., content, structural, external, generalizability, substantive, and consequential). To examine each validity dimension, the Rasch model was considered. To this end, the data of 394 test takers who had taken the test in 2023 were cleaned and analyzed for the assumptions of the Rasch model and then for the 6 aforementioned validity aspects. The results indicated that the structural (i.e., unidimensionality), generalizability (i.e., measurement invariance), and substantive aspects held. However, the evidence for the content, external, and consequential aspects of validity was less definitive. The implications of the findings for the validity of the test, for the realm of language testing, and for item developers and item writers will be discussed.