Pre-service teachers (n = 1572) from five faculties of education in Ontario, Canada were surveyed at the beginning of their programme about their attitudes and self-efficacy beliefs regarding inclusive practices. These responses were compared to responses from Ontario in-service teachers (n = 739) prior to their district-wide shift from a model of segregation to inclusive classrooms. Results demonstrate that elementary and female pre-service teachers held the most clearly defined inclusive growth mindset and indicated a greater level of confidence in communicating with and supporting families of students with disabilities as compared to secondary and male pre-service teachers. Male pre-service teachers had higher self-efficacy than females for managing behaviour in the classroom. Pre-service teachers, as compared to in-service teachers, favoured a student-centered classroom that promotes student choice and differentiated instruction and they indicated greater confidence in their ability to engage students with accommodations. Pre-service teachers held distinct attitudes toward the role of the students in their own learning and their responsibility to teach to all. It is important to note that both sets of participants were at the beginning of their inclusive practice, therefore, the role of lived professional (or lack thereof) experience may be impacting their attitudes and self-efficacy beliefs about inclusion.