The purpose of this study was to identify the types of peer scaffolding used by Thai EFL students while completing reading activities. Pre-test, post-test and reading test procedures were implemented to measure the impact of peer scaffolding on students' reading comprehension. The peer scaffolding checklist was employed to identify the types of peer scaffolding the EFL students used in the reading classroom. This study found that the EFL students gained higher post-test mean scores after engaging in reading activities along with peer scaffolding strategies. The beginner and elementary EFL students mostly used procedural assistance, whereas the intermediate EFL students frequently used sharing and questing as peer scaffolding. These findings may provide sociocultural theoretical and pedagogical implications for EFL teachers when supporting peer scaffolding and assisting EFL students to develop reading comprehension.