The current study attempted to investigate and compare the perceptions of Iranian in-service hard disciplines, soft disciplines, and English teachers of their prognostic, formative, and summative assessment literacy. To this end, a total number of 282 high school teachers (94 teachers from each disciplinary groups) were asked to complete the modified and validated version of Rahimi and Rastgoo’s (2017) questionnaire. To enrich the quantitative phase, 90 teachers (30 ones in each group of disciplines) were also interviewed. The results of one-way ANOVA and multiple comparisons revealed a significant difference between hard disciplines and English teachers in terms of their prognostic and summative assessment literacy. However, no significant difference was found among the three groups in terms of their formative assessment literacy. The content analysis of the interviews cast light on the commonalities and discrepancies of assessment perceptions and practices depending on the teachers’ disciplines. The findings can be transferred to teacher education programs to enhance the teachers’ subject-specific assessment competencies.
