This mix-methods study aimed to explore the impact of scaffolding genre knowledge on English as a Foreign Language (EFL) graduate students’ academic writing skills. The initial population included 100 (62 females and 38 males) M.A. Teaching English as a Foreign Language (TEFL) students who took advanced writing course. They were selected from Islamic Azad University, Tehran and Alborz branches. The method for sample selection was convenience sampling. Oxford placement test (OPT) was employed to homogenize the sample, and 50 advanced learners, including 31 females and 19 males, were selected based on its results. Next, they were divided into an experimental group and a control group in which the experimental group was taught based on scaffolding genre knowledge, and the control group received instruction according to the class regular syllabus. After that, IELTS academic writing task 2 was used as the pretest. The treatments lasted for 16 sessions, and each session took 90 minutes. Upon finishing the treatment, the same IELTS academic writing task 2 was run as the posttest. Then, the researcher-made questionnaire was administered to the experimental group’s students to measure their perceptions quantitatively regarding genre knowledge. To explore the students’ perception concerning the instructions qualitatively, the semi-structured individual interviews were administered to ten students who were chosen from the experimental group. The results showed that scaffolding genre knowledge had significant impact on the Iranian EFL learners’ academic writing skill. Furthermore, the qualitative findings showed that the learners adopted positive views toward scaffolding genre knowledge in developing their academic writing skills.