This study investigated the impact of teacher and peer scaffolding on the speaking performance of Iranian EFL learners. Utilizing a quasi-experimental design, 60 intermediate-level female learners were selected from a population of 75, divided into three groups: teacher scaffolding, peer scaffolding, and a control group. The study employed the Preliminary English Test (PET) and speaking pretest and posttest to ensure homogeneity and measure the participants’ progress in speaking proficiency. The results of a One-way ANOVA indicated significant improvements in speaking performance for both scaffolding groups compared to the control group. However, no significant difference was found between the effects of teacher and peer scaffolding. These findings suggest that both types of scaffolding are equally effective in enhancing L2 speaking skills, supporting the theoretical framework of Vygotsky’s Zone of Proximal Development (ZPD). The study underscores the importance of incorporating scaffolding into language instruction to foster better speaking outcomes. Manuscript profile