The importance of the stereotypes and teachers’ beliefs about mathematics as the male domain, for the students’ perception of their competences and achievements is the subject of extensive research. It is generally assumed that teachers – as guardians of socialisation – replicate this stereotype. An attempt to measure the stereotypical teachers’ assumptions has been offered only by J. Tiedemann (2002). It has become an inspiration to design the authors’ own research programme in which the relationship between increased stereotype beliefs and teachers’ asymmetry of female and male students’ abilities is sought. The paper presents the results of the study of the Polish version of the Gender Stereotypes Scale among 120 mathematics teachers (95 female, 25 male) from junior high schools. It has been shown that a) the stereotype is irrespective of the teacher’s gender, b) its profile is different in the sample of male and female respondents, c) the length of employment does not differentiate it. The educational implications of the obtained data have been presented in the paper.