The study aimed to identify the most important psychological and environmental variables related to intellectual extremism from the perspective of secondary school students and their teachers in Afif Governorate, Saudi Arabia. The sample of the study consisted of (350) secondary school students (200 males and 150 females) and (252) male and female secondary school teachers from Afif Governorate, in the academic year 1440/1441 H. The researcher used the descriptive method, as well as the scale of psychological and environmental variables towards intellectual extremism in secondary school prepared by him. The results of the study showed that there are no significant statistical differences in the psychological and environmental variables in its four dimensions that are associated with intellectual extremism among secondary school students from the point of view of the teachers due to the gender (male teacher- female teacher) and specialization variables except for the cognitive dimension in relation to the scientific specialization, and it showed statistically significant differences with regard to the more than ten years' experience variable except with the environmental effects.