The study was designed to investigate teachers’ practices through National Professional Standards for Teachers in Pakistan at secondary school level in Lahore. Practices of teachers investigated through NPSTP (National Professional Standards for Teachers in Pakistan), delimited to four standards including human growth and development, instructional planning and strategies, assessment and professional development and code of conduct. Data were collected through two questionnaires, filled by teachers and their students. Sample was 539 (241male and 198female) teachers and 1044 students of 9th and 10th classes from 72 boys and girls secondary schools of Lahore. An observation conducted for twenty eight classrooms to investigate the practices of teachers in classroom. The statistical techniques as chi square, Cramer’s V value and percentage were applied for data analysis by using SPSS (Version20). Major findings of study indicated that though the teachers were aware of NPSTP to some extent but they were not practicing these standards in their classrooms efficiently. It was suggested that the teachers should be trained according to the National Professional Standards for Teachers in Pakistan.