The underrepresentation of females in Science, Technology, Engineering and Technology (STEM) careers is a global issue and recently, early childhood has been forwarded as a critical developmental phase for cultivating positive dispositions towards STEM. There is emerging evidence of the effects of gender stereotype beliefs held by teachers on beliefs and behaviours of preschool aged children (c.f. Chapman, 2016). Gender stereotype beliefs develop through the life course and have been shown to negatively impact females’ self-concept in STEM (e.g. Ertl et al., 2017), which ultimately impedes their future orientations towards studying these areas. Of importance to the present work, an individual’s gender stereotype beliefs can be influenced by significant others (e.g. peers and teachers) which presents a necessity to examine the role of the early childhood educator and the potential etiology of any implicit gender biases.The aim of this quantitative study was to investigate the existence of implicit gender stereotype beliefs amongst a cohort of pre-service early childhood teachers. Additionally, the paper presents evidence on the interaction of these beliefs with level of previous mathematics study (common subject to all students in secondary education) and self-concept, to determine whether these variables are predictive of attitudes towards STEM. Participants in the study were pre-service early childhood teachers (N=74) in the 3rd year of study of an undergraduate programme. Electronic surveys utilising a series of pre-established scales were distributed and statistically analysed. Scales measured gender stereotype beliefs (from cultural and ability perspectives), mathematics self-concept and attitudes towards STEM. Findings indicate that participants held implicit gender stereotype beliefs towards ability in the STEM fields, indicating that males would perform better than females (t(73) = -11.85, p< .001) and that STEM fields of study were culturally more masculine in nature (t (73) = 6.15, p < .001, eta squared = .34). Regression analysis revealed that previous level of mathematics study, mathematics self-concept and implicit gender stereotype beliefs significantly predicted overall attitudes to STEM. The findings of this research confirm that gender stereotyped ability beliefs persist. Similar to Wolter et al. (2015), who found preschool teachers gender stereotype endorsement favoured girls ability in reading, our findings indicate a stereotype bias attributing superior male ability in STEM. In addition, these beliefs explain some of the variance in predicting overall attitudes to STEM beyond previous level of mathematics study and self-concept. These findings have significant implications for the teaching of STEM in the early childhood classroom.