This study explores the role of group-based scaffolding in improving academic writing skills among EFL university students. Guided by Vygotsky’s socio-cultural theory and the Zone of Proximal Development (ZPD), the research examines cognitive, social, and linguistic scaffolding across three phases of collaborative writing: pre-writing, while-writing, and post-writing. Data was collected from nine EFL students in three groups with varying English proficiency levels to observe how scaffolding facilitates learning. The findings show that cognitive scaffolding predominates in the pre-writing phase, while social scaffolding is crucial for group cohesion throughout all phases. In the post-writing phase, linguistic scaffolding becomes central as students refine language accuracy. The study highlights the adaptability of peer support in meeting evolving student needs and enhancing writing outcomes, suggesting the effectiveness of group-based scaffolding in EFL contexts.This study explores the role of group-based scaffolding in improving academic writing skills among EFL university students. Guided by Vygotsky’s socio-cultural theory and the Zone of Proximal Development (ZPD), the research examines cognitive, social, and linguistic scaffolding across three phases of collaborative writing: pre-writing, while-writing, and post-writing. Data was collected from nine EFL students in three groups with varying English proficiency levels to observe how scaffolding facilitates learning. The findings show that cognitive scaffolding predominates in the pre-writing phase, while social scaffolding is crucial for group cohesion throughout all phases. In the post-writing phase, linguistic scaffolding becomes central as students refine language accuracy. The study highlights the adaptability of peer support in meeting evolving student needs and enhancing writing outcomes, suggesting the effectiveness of group-based scaffolding in EFL contexts.