Based on the demands of the twenty-first century, student-centered learning is becoming increasingly crucial. English teachers at SDMT Ponorogo employed collaborative learning approaches that emphasized student-centered activities to promote engagement, shared accountability, and peer learning. This study aimed to identify the implementation of this strategy and describe challenges and outcomes, particularly in terms of students' social interactions during classroom learning.

In this study, the researcher used the qualitative method with a study case approach. The subjects of this study are 4 English teachers who implemented collaborative learning strategy in SDMT Ponorogo. The reason why the researcher chose them is because they have experience in implementing collaborative learning. To collected the data, the researcher used interview, observation, and documentation. This study used descriptive analysis method by Miles and Hubermen interactive model that carried out though several stages.

The results of this study showed that 100% of the English teachers in SDMT Ponorogo implemented a collaborative learning strategy for teaching English. Teachers applied collaborative learning strategies such as conducting problem-solving activities, role-playing, project-based learning, etc. The researcher also found that both the teachers and students faced several challenges when implementing collaborative learning. The outcomes of collaborative learning enhance students both in study and social interaction.

In conclusion, the implementation of a collaborative learning strategy yields positive outcomes for both academic and social interaction. Despite experiencing various challenges, the teacher's role in planning, actualizing, and evaluating makes the collaborative learning process run successfully. Future researchers should explore the long-term impact of collaborative learning on students’ academic and social development. Besides also addressing the challenges between the teachers and the students.