This study examined relationships between three factors related to teacher self-efficacy (use of inclusive instruction, collaboration with others, and managing disruptive behaviour) and practicing teachers' sentiments, attitudes, and concerns about inclusive education of students with developmental disabilities. We calculated Pearson product-moment correlations to examine individual associations and conducted a series of multiple regression analyses to determine which associated factors, when considered simultaneously, were most predictive. Results indicated that higher self-efficacy for collaboration was the only predictor associated with more positive sentiments and attitudes and with fewer concerns about inclusive education for students with developmental disabilities. The results replicate the findings of a previous study on this topic and highlight the importance of both pre-and in-service education aimed at providing educators with dispositions and skills related to effective collaboration with parents and other members of a school-based team.