Medium of instruction (MOI) policymaking is an important line of inquiry in language policy and planning (LPP) studies, emerging at two levels of de-jure, official, and explicit level on the one hand, and de-facto, unofficial, and implicit, on the other. Nowadays, an increasing interest in MOI studies is evident since such studies carry significant implications to the complex dynamics of who does what for what purposes and why in LPP studies in general as well as to a deeper understanding of bilingual and multilingual students’ academic achievements in diverse linguistic settings. Despite the significance of the subject, studies addressing MOI policymaking and implementation in Iran are scanty. Accordingly, this study aims to bridge this gap by examining MOI policymaking at de-jure and de-facto levels in Iranian primary schools with a focus on two communities namely Azerbaijani Turkish (Az Turkish) and Kurdish. This study follows grounded theory methodology. In this regard, LPP documents concerning MOI in Iran were used to examine the former level, while 47 teachers participated in semi-structured interviews to investigate the latter. Data were coded and analyzed using MAXQDA software. Findings at the de-jure level indicated that there were two key themes underpinning Iran’s MOI policymaking: security and pluralistic perspectives. De-facto MOI policymaking, however, was found to follow different trajectories. Interestingly, more discrepancies between official and teacher MOI policymaking were documented among Kurdish primary school teachers. Overall, findings suggested that ‘student-related factors’, ‘courses of instruction factors’, ‘materials factors’, ‘official status of Farsi’, ‘teacher-related factors’, and “factors pertaining to official regulations” affect and shape Azerbaijani and Kurdish teachers’ MOI policymaking in Iran. The findings of this research can be helpful for policymakers and instructional material designers.
