Teacher cognition research has gained a lot of attention during the past years and it is because of the growing interest in finding how teachers' cognition are shaped and how they are reflected in their classroom practices. according to the scholars, since teacher cognition is a context-dependent concept, so the examination of its relationship with their teaching practices cannot be done without considering the context. the relation of teachers' cognition with their classroom practices was attended by this study with a tendency to attending to the learning environment. so far as number of studies paid attention to second language teacher cognition in the context of Iran; however, as was examined, teachers' cognition and practice with regarding to the school environment have not yet been attended. the current study aimed to fill this gap through revealing iranian EFL high school teachers' cognition about their school environment and investigating its relationship with their teaching practices in the classroom in Arak. to find this relationship, this study fulfilled three steps. the first was to investigate teachers' idea about their school environment, the second was to investigate their performance in the classroom, and the third was to examine the physical environment of the selected teachers' schools. the study population comprised 35 second-stage state high schools, 16 males and 21 females, from two educational districts of Arak. the sample consisted of 52 EFL teachers (22 males and 30 females), who were included based on their required qualifications for this study. 71 questionnaire (from 31 males and 40 females) were totally gathered, as 15 teachers completed the questionnaire in 2 school, 2 teachers completed in 3 shcools, and 35 teachers completed in 1 school. three instruments were used for the purpose of data collection, namely questionnaires, classroom observations and codifying the classroom transcriptions. school-level environment questionnaire (SLEQ), w