To capture the unique nature of collective teacher efficacy as reflected in ELT settings, the current study attempted to develop and validate a context-specific collective efficacy scale and use it in exploring collective efficacy beliefs in different ELT contexts. To achieve this goal, guided by the related literature, the most prominent constituent elements of collective teacher efficacy were identified through a series of semistructured interviews with English language teachers and instructors in educational contexts of school, institute, and university. Based on the seven-component initial model obtained from qualitative content analysis, a 32-item questionnaire was developed and tried on 405 EFL teachers and instructors. The data were then subjected to exploratory factor analysis. The proposed model consisted of 21 items encompassing four factors. The results of the confirmatory factor analysis indicated that the scale showed indices of construct validity and suitably fit the proposed collective efficacy model. Applying a one-way ANOVA also revealed that the three educational contexts differed significantly with respect to English teacher collective efficacy beliefs. English language institute teachers displayed the highest collective efficacy level while university instructors showed the lowest level. A significant difference existed between institute and high school teachers and university instructors.