School environment has been considered in literature as an important factor which influences the behaviour and performance of teachers. Several aspects of school's psychosocial environment have been cited as strongly related with teacher commitment, efficacy, morale, stress, burnout, attrition and turnover. This study explored the perceptions of private school teachers of Karachi about their school's psychosocial environment. It used School Level Environment Questionnaire (SLEQ) for this purpose' thus, it also validated the tool. SLEQ was self-administered to a sample of 289 teachers, selected from two towns of Karachi, Pakistan, through a multi-stage cluster sampling. Factor analysis was used to explore the perceptions of teachers within the three dimensions of school environment, which are: Relationship Dimension (RD), Professional Development Dimension (PDD), and System Maintenance and System Change Dimension (SMCD). In relationship dimension, the findings of the study reveal that generally teachers perceive healthy relationships with their students and colleagues. Most of the teachers believe that their students are helpful, cooperative, well-mannered and respectful; however, some teachers also think that students are noisy and disruptive; and hence, they consider using strict disciplinary measures to control them. In relationship with their colleagues, they generally perceive a collegial atmosphere and friendly relationships; however, some teachers also feel that they are not appreciated by their colleagues and their voice is not given importance. In the professional development dimension, teachers feel that they have opportunities for learning and professional development in their school environment. They frequently discuss professional matters, talk about teaching and learning, attend training courses, and are keen to learn from each other. In system maintenance and system change dimension, the findings report that most of the teachers feel that their schools provide them adequate resources, including computers and internet, which according to teachers, are highly related with innovation in their teaching. The teachers also believe that they have a certain level of work pressure in their schools, with some teachers feeling that they have little time to relax and their workload is unmanageable. Teachers mostly feel that they have lack of freedom and authority, as they are expected to strictly follow the syllabus and lesson plans and use the prescribed material and textbooks. Most of them believe that decisions in their schools are usually taken by principal and a small group of teachers, and they are not allowed to take decisions on their own as they are usually expected to refer to the