One of the factors linked to the successful inclusion of children with autism spectrum disorder (ASD) is the idea that the attitudes of teaching professionals are related to the perceived efficacy of educational practices. The aim of this study was to explore the relationships between the perceived efficacy of a set of practices specifically aimed at children with ASD and the perceived drivers and attitudes toward their full inclusion. We estimated a structural equation model that included socioprofessional variables of the 454 teachers taking part in the study. The results show that greater efficacy of the practices implemented with children with ASD results in more positive attitudes toward the education of these children in inclusive settings. Similarly, drivers of inclusion also improve teachers' attitudes toward these children. The findings suggest the need to improve teacher training and provide teachers with the resources necessary to adapt their practices to all children.