The aim of this research was to predict studentschr(chr('39')39chr('39')) academic procrastination based on metacognitive beliefs about procrastination with the mediating role of test anxiety The research method was descriptive-correlational. The statistical population included all undergraduate students of Shahid Beheshti University of Tehran in the academic year of 2019-20, from which 320 (206 females and 114 males) were selected by multi-stage cluster sampling. The Procrastination Assessment Scale for Students, Spielberger test anxiety questionnaire and Metacognitive Beliefs about Procrastination Scale were used to collect data. Data were analyzed by structural equation modeling. Findings showed that the suggested conceptual model has a good fit with the data. The variables of test anxiety and metacognitive beliefs about procrastination accounted for most of the variance in academic procrastination, respectively, and explained a total of 28% of its variance. Negative metacognitive beliefs about procrastination only indirectly affected academic procrastination through test anxiety, and full mediation was endorsed. According to the results, it can be concluded that negative beliefs about procrastination make students prone to test anxiety and academic procrastination. Therefore, modifying these beliefs can be considered as an intervention program to decrease test anxiety and academic procrastination.