A belief in one’s ability to enact change is central to personal motivation, and thus the way we behave (Bandura, 1993). More particularly, mathematics teaching efficacy beliefs encompass the extent to which a teacher believes that his/her teaching is capable of bringing about change in the mathematical understanding of his/her students, and the extent to which teaching in general supports the learning of mathematics for all students. Bandura (1993) further posits that teachers with a low sense of efficacy are less inclined to support students in responding constructively to challenge and may thus undermine students’ sense of self efficacy in relation to mathematics. This is particularly significant when students’ transition from primary to secondary school, a change that frequently has a negative impact on students’ achievement and enthusiasm for mathematics (Grootenboer & Marshman, 2016). This cross border research study sought to capture the mathematics efficacy beliefs of 6th class and Year 7 teachers in the Republic of Ireland (ROI) and Northern Ireland (NI), respectively, as well as 1st Year and Year 8 teachers through the use of a questionnaire. Altogether, a representative sample of 428 primary teachers responded, 298 from ROI and 130 from NI and 248 secondary mathematics teachers, 173 from ROI and 75 from NI. The findings show a disparity in relation to teachers’ impressions of mathematics. Primary school teachers (57.8% NI, 57.5% ROI) consider mathematics easier than most subjects to teach with only around 10% of secondary teachers agreeing (8.1% NI, 12.9% ROI) (chi sq p<0.0001). All teachers reported a high sense of self-efficacy in relation to answering students’ questions in class as well as teaching all strands across the mathematics curriculum. Primary teachers were more likely to consider that students were well prepared in all strands of the curriculum upon exiting primary school than secondary teachers. This disagreement is more pronounced when considering Algebra than in any other strand (89% primary, 11% secondary). Particularly significant is that in NI 72% of secondary teachers as opposed to 51.5% of primary teachers agreed that students have their minds made up about mathematics before they start in secondary school (p=0.006) pointing to a lower outcome expectancy. These findings are particularly pertinent considering that the national Growing Up in Ireland study capturing the transition of students from primary school concluded that the quality of students’ interaction with secondary teachers emerged as having a significant relationship with attitudes to mathematics (ESRI, 2017, 52).