This study examines the intricate relationship between teacher discourse and student engagement in English as a Second Language (ESL) classrooms within Karachi schools. Grounded in a qualitative research design, the investigation explores the impact of three key dimensions of teacher discourse—Clarity and Comprehensibility, Encouragement and Support, and Interactive Communication—on student engagement. Classroom observations were conducted across a diverse range of schools to capture a comprehensive view of these interactions. The findings of the study affirm the crucial role that teacher discourse plays in shaping student engagement. The analysis reveals that when teachers communicated with clarity and employed comprehensible language, student engagement levels were notably elevated. Such environments facilitated active participation and comprehension, aligning with previous research highlighting the fundamental importance of clarity in pedagogy. Encouragement and support from teachers emerged as another influential factor in promoting emotional and cognitive engagement. The positive atmosphere created by supportive teacher behavior fostered a greater willingness among students to contribute, ask questions, and partake in discussions. This underscores the significance of emotional connection within the learning environment. The study also underscores the value of interactive communication between teachers and students. Classrooms characterized by dialogic interactions and open-ended questions witnessed heightened levels of student engagement. These findings extend existing literature on the benefits of interactive teaching methods, showcasing their potential to enhance both cognitive and emotional engagement. The implications of these findings underscore the importance of incorporating effective teacher discourse strategies into educational practices to cultivate more engaging ESL learning environments.