Cooperative learning and differentiated instruction have recently attracted a lot of attention as they are considered by educators and teachers to play significant roles in motivating learners and promoting interactive learning. The present study aims to examine English teachers' views about the effectiveness of the practice of cooperative learning and differentiated instruction in enhancing students' learning in English language classes. A sequential mixed method was used to collect the necessary data to answer the research questions. A questionnaire was first sent to 200 English language teachers, and then the researchers conducted focus group interviews with eight teachers. The findings of the study reveal that English language teachers consider cooperative learning as a valuable instructional procedure for promoting learners' engagement, classroom social interaction, cultural appreciation, and differentiated instruction. The present study's findings may have implications at all levels, such as teacher training, academic administration, curriculum designing, and decision making. Applications of those findings may attract the attention of others beyond the English classes. In addition, the findings may provide valuable guidance for researchers and educators to carry out large scale studies on the practice of cooperative learning and differentiated instruction in English language classes within the present study's context and beyond.