The main aim of the current study was to investigate the effect of the six hats' strategy on enhancing supervisory skills of English mentors and their intellectual flexibility. The study was conducted in Beni Suef educational district. Twenty- five EFL mentors at the preparatory stage acting on as one study group were trained on supervisory skills using six hats' strategy. The study instruments represent in a situational test for the supervisory skills in addition to a scale for measuring the intellectual flexibility . Sessions based on six hats' strategy were used as the material of the study. Statistical analysis of the data revealed that there were statistically significant differences between the mean scores of the study group students in pre - post administrations in the supervisory skills' situational test as well as in the intellectual flexibility scale in favor of the post administration. The magnitude effect was big; thereby proving the effect of the six hats' strategy.