Critical thinking is a fundamental cognitive skill that significantly influences our thought processes. Without it, reaching impartial and accurate conclusions becomes challenging. This skill holds profound importance in educational settings. The focus of the present study was to examine how teaching critical thinking skills enhances the critical thinking and reading comprehension abilities of Iranian English as a Foreign Language (EFL) learners. A group of 40 in-service EFL teachers from Farhangian University in Iran underwent pretests on reading comprehension and critical thinking. Critical thinking interventions were systematically integrated into the course curriculum at 4-week intervals. Following the instructional period, posttests were conducted to evaluate the effectiveness of the critical thinking intervention program. Results indicated a notable improvement in both the knowledge and attitudes towards critical thinking. Moreover, the program positively impacted the students' reading comprehension levels, particularly their ability to critically approach reading comprehension tests. This highlights the significance of creating an environment where students feel comfortable expressing their thoughts without the fear of judgment. Educators play a crucial role in fostering optimal critical thinking behaviors and attitudes through effective modeling. Promoting a culture of open expression and critical thinking is key to nurturing well-rounded learners.