Peer teaching refers to the process of students teaching other students and has been applied in various contexts because of its positive impact on student academic performance as well as its social and cognitive values. Yet, most research on peer teaching tends to be long-term programmes with fixed student tutors and is mostly conducted in the field of science. This research, therefore, aims to examine the effectiveness of reciprocal peer teaching in a 50-minute EAP lesson to undergraduate students in a transnational university in China. Students alter their roles to teach and be taught by their peers on provided materials. Retention of knowledge was tested after 2 weeks to investigate the effectiveness of peer teaching, and a questionnaire-based survey was conducted to gather students’ perceptions of this learning approach. Results show that peer teaching has a positive impact on student retention rate, especially for student tutors. Students’ perception of reciprocal peer teaching is mainly positive but mixed with concerns, particularly regarding unguaranteed teaching quality. Further considerations have been discussed in this regard. Future research is also recommended to expand peer teaching in other teaching contexts and combine peer teaching with other instructional methods to better facilitate learning.