The purpose of this research is to check the efficacy of blended mode of learning in ESL (English as a Second Language) classrooms in Pakistan under the theoretical construction of Transactional Distance Theory. For this purpose, the data was collected for pre-test, post-test and self-administered questionnaire from 499 ESL learners of private universities in Pakistan which were offering the blended learning programs. The post-test results indicated significant improvement in student's English language proficiency. In the same vein, the Partial Least Square (PLS)-Structural Equation Modelling (SEM) techniques results confirmed that most of the factors namely ease of use, computer literacy, need for face-to-face interaction, pre-built learning mechanism and resistance to change have a significant relationship with blended learning except the two factors namely, technical difficulty during the attempt and student assistance in lab.