Autonomous learning and social activity have excessively been the focus of interest in second language acquisition over the past decades. The present study aimed to explore how activity theory-as a branch of sociocultural theory focusing on social context-can promote Iranian EFL learners’ autonomy. To this end, fifty-six EFL students studying English translation at the Islamic Azad University, Tehran Central Branch, participated in the study. The participants were assigned to two groups, one experimental group and one control group. At the beginning of the semester, both groups took a language proficiency test to ensure their homogeneity. They also completed an autonomy questionnaire as the pre-test and post-test. The instruction in both groups was based on a five-step process of developing the academic writing skill, including prewriting, organizing, writing the first draft, revising and editing, and writing a new draft. However, only the experimental group received the instruction through an e-learning platform designed based on the six elements of activity theory-subjects, objects, mediating artifacts, rules, community, and division of labor-suitable for EFL writing classrooms. The results revealed that integrating activity theory to e-learning had a decisive role in enhancing the students’ learner autonomy. It is hoped that the findings raise both teachers and students’ awareness of implementing activity theory as a social learning framework to foster autonomous learning in EFL contexts.