Scaffolding is help provided by a teacher to a student to achieve a desired goal. It is viewed as an effective technique that enhances both collaborative skills and writing ability among EFL learners. The present study sought to explore the possible effects of two kinds of scaffolding, that is, teacher and student scaffolding, on EFL students' writing ability. To this end, 45 lower-intermediate and 15 upper-intermediate EFL participants from Gonabad, Iran were selected based on a Quick Placement Test (QPT). The participants formed two experimental groups (peer scaffolding, teacher scaffolding) and one control group. Participants in the experimental groups underwent scaffolding techniques, which required lower-intermediate EFL students to be assisted by more proficient EFL students in one experimental group while in the other experimental group, assistance was provided by the teacher. A series of t-tests was run, and the results indicated the effectiveness of the two kinds of treatment implemented in the two experimental groups. Also, no significant difference was found between the two experimental groups in the post-test regarding the effectiveness of teacher scaffolding and peer scaffolding. These findings provide pedagogical implications for employing scaffolding techniques in EFL contexts by both teachers and high-level students.