Postmodernism represents skepticism toward metanarratives and universal ideologies that dominated the modernist era. The study focuses on three key postmodernist concepts - alternative assessment, process syllabi, and self-directed learning. Alternative assessment emphasizes evaluating the learning process over summative testing. Process syllabi focus on the learning experience rather than rigid outcomes. Self-directed learning enables student responsibility in setting learning goals and processes. This paper examined the effects of postmodernist educational concepts on improving Iranian EFL learners’ Autonomy. A quasi-experimental pre-test/post-test design was utilized with 60 intermediate level Iranian EFL students divided into an experimental and control group (n=30 each). The experimental group received instruction utilizing the three postmodernist concepts over 14 weeks, while the control group received traditional modernist instruction. Autonomy was measured using a validated questionnaire before and after the intervention. The results showed the experimental group demonstrated significant increases in Autonomy compared to the control group. Paired sample t-tests revealed significant differences between pre-test and post-test Autonomy for the experimental group across all three postmodern concepts - alternative assessment, process syllabi, and self-directed learning. This suggests postmodernist concepts that decentralize instruction and emphasize student process over outcomes can enhance Iranian EFL learners’ self-direction and responsibility for language acquisition. The study implies EFL syllabus designers and instruction should transition to postmodern models centered on individualized assessment, flexible syllabi, and student-guided learning to boost Autonomy. Further research can expand sample sizes and explore additional postmodernist concepts across diverse demographics.