Teachers, students, and the administrative body are the key components of school culture as they comprise overall school activities. If these components are not adequately channelled, teachers cannot achieve a high level of professional commitment and performance. With this mindset, this study explores Nepalese English language teachers' perceptions of school culture and its role in their professional commitment. The perceptions and practises of three English language teachers who teach English at secondary schools in the Kathmandu Valley are investigated. The findings revealed that school culture is the place for professional roles and responsibilities. Similarly, Nepalese English language teachers perceive school as a language lab and a place for changing, modifying, and correcting professional behaviours. Additionally, they perceive school culture as a system of standards, beliefs, and rules that govern how people behave in social, cultural, and religious contexts. Moreover, they believe school culture affects their wellbeing and professional growth. In the case of practice, healthy relations in school developed an excellent spirit of performance, whereas domination and discouragement by the school leaders reduced personal commitment and increased the chances of teacher burnout. A good level of teacher commitment and confidence was achieved with the family environment in school, but the unintellectual ideologies of school owners and leaders did not focus on teachers' development, resulting in teacher disappointment. Mutual understanding, supportive nature, cooperative behaviour, and a learning attitude among school staff were expected for better commitment and performance by English language teachers.