Co-teaching is a method that two teachers work together and deliver the instruction in the same classroom to a heterogeneous group of learners. This study was an attempt to find out the effect of one teach-one assist model of co-teaching on Iranian EFL learners’ reading comprehension. To this end, a quasi-experimental design with the pre-test, post-test, and control group was employed and 35 female students within the age range of 15-18 at the elementary level were selected as the participants of the study from Sanjesh-E-No institute in Tabriz, Iran. They were randomly assigned into the experimental and control groups after taking Key English Test (KET). The experimental group received instruction through two teachers while the control group was taught by a single teacher. Both groups took part in the pre-test and post-test of reading comprehension. The results of an independent-samples t-test revealed that the experimental group had significantly better reading performance compared to the control group. The results of the study can be useful for teachers, students, and any ELT program.
