In line with the theory of planned behaviour, different factors influencing the formation of attitudes and beliefs indirectly affect the intentions that determine an individual’s behaviour. Hence, it is important to examine the factors affecting the attitudes of preschool teachers towards children’s gender roles considering that their own understanding of gender roles influences their behaviour towards children in kindergarten (which can be in agreement with the egalitarian or stereotypical attitudes of preschool teachers). Therefore, a quantitative research was conducted in Zagreb (Croatia) on a sample of 481 preschool teachers. The research was aimed at determining the effects of socio-demographic characteristics, religious (non)affiliation and personal experiences of gender discrimination during childhood on the attitudes of preschool teachers towards children’s gender roles and on the frequency of noticing unequal treatment of boys and girls in kindergarten by other preschool teachers. The findings revealed that preschool teachers who have identified themselves as non-religious or religiously non-affiliated who were brought up in larger cities, with a personal experience of gender discrimination in childhood, more frequently notice unequal treatment of boys and girls in kindergarten (by other preschool teachers). Among the mentioned variables, the strongest effect on noticing unequal treatment of boys and girls in kindergarten has the variable experience of gender discrimination during childhood which confirms greater awareness of gender discrimination among persons who experienced such discrimination.