This paper reports a two-phase study. Phase 1 of the study was aimed at developing a self-report scale based on which to analyze language teachers' perceptions toward the inclusion of critical thinking components in language teaching materials. To this end, we developed a 17-item Criticality-oriented English Teaching Perceptions Inventory (hereafter CETPI). In Phase 2 of the study, we examined the reliability and construct validity of the CEPTI using data collected from 150 teachers of English as a Foreign Language (EFL), mainly through employing the Exploratory Factor Analysis (EFA). The results indicated that the CEPTI enjoys a high internal consistency (α=0.93). Further, having determined a factorable sample through the Kaiser-Meyer-Olkin (KMO) test of Sampling Adequacy and Bartlett's Test of Sphericity, EFA was applied to the data. Moreover, the results obtained from Principal Component Analysis (PCA), the Scree Test, and the Component Plot in Rotated Space all supported a three-factor solution for the grouping of the items in the inventory.