Abstarct: Learners in EFL settings usually face various challenges when it comes to speaking in general and taking international tests in particular. Despite cognitive apprenticeship’s studies in other contexts, there was a dearth in focusing on its application to speaking skills, so this study investigated the effect of cognitive apprenticeship on the IELTS speaking proficiency of intermediate Iranian EFL learners. It followed a randomized pretest-posttest control group design, including sixteen treatment sessions. This study involved 60 participants from two intact classes of two different institutes in Kermanshah Province, Iran, aged 20 to 30, who were selected through random sampling and were assigned randomly into two groups (30 in the control group and 30 in the experimental group). The Preliminary English Test (PET) and two IELTS speaking tests were employed as instruments. Trained examiners assessed participants’ performance by using the IELTS speaking scoring guideline, which considered criteria such as fluency, coherence, lexical resource, grammatical range and accuracy, and pronunciation. The experimental group received cognitive apprenticeship six stages proposed by Collins et al. (1991), namely modeling, coaching, scaffolding, articulation, reflection, and exploration, while the control group followed conventional instruction. Descxriptive and inferential statistics were employed to analyze the data, including independent sample t-tests and paired-sample t-tests. The results indicated that the experimental group outperformed the control group in terms of speaking proficiency (p=0.00, <.05). The study contributed to the understanding of effective pedagogical methods in language instruction and offered insights to enhance language learners’ speaking skills.