Abstract-the purpose of the present study was to investigate the impact of teaching critical thinking skills on reading comprehension of Iranian intermediate EFL learners. A sample of 50 students from Arshia Language Institute in Ilam, Iran participated in this study. They were both male and female students who were selected among 80 students based on their performances on PET. The participants were randomly divided into experimental and control groups. First, the two groups were exposed to the pre-test of reading comprehension in order to evaluate their knowledge on reading before the treatment. Based on scores obtained from the Pretest, no significance differences were observed between two groups. After that the treatment was started and the experimental group was exposed to teaching critical thinking skills. Meanwhile, traditional methods of teaching reading comprehension were used for teaching reading comprehension to the control group. Finally, post-test of reading comprehension was delivered to both groups at the end of treatment to check possible differences. To analyze the collected data, ANCOVA was run using SPSS Software Version 16. The results showed that teaching critical thinking skills positively affect reading comprehension of intermediate EFL learners, but the interaction of gender and teaching critical thinking was not significant.