Language teachers must meet students' unique requirements in differentiated classrooms. It can be difficult for second language teachers to customise materials and procedures to students' readiness, talents, and social experiences. This study uses Tomlinson's (2015) differentiated instruction to encourage teachers to customise content, process, and product for second language (L2) learners. At two phases, an explanatory sequential mixed method approach was used: Initial research examined bias tasks via cooperative learning (BTCL) in reading comprehension classrooms. The goal was to assess 60 high, middle, and poor performers' reading comprehension. To analyse quantitative data, one-way ANCOVA was used. A focused group interview was conducted during the qualitative phase to assess the BTCL's reading classroom effectiveness after the intervention. A detailed content study of 10 EFL learners' iterative reading of transcribed interviews was qualitative data analysis. The data were coded into reductionist themes using open, axial, and selective methods. Data analysis and interpretation were done using MAXQDA. The results showed that the BTCL's main implications were motivation and reading meaning-building. Using this method in the classroom led to subcategories like decision-making, creativity, conceptualising, and grasping main ideas. The results showed that BTCL inclusion in EFL classrooms improves reading comprehension. These findings affect language learners and teacher training. پرونده مقاله