Teacher efficacy represents a key construct in exploring successful implementation of inclusive policy. Teachers' impression of school climate is shown to relate to teacher efficacy; however, few studies pay due deference to its context/specific conceptualisation, with a particular lacuna in research noted in an Irish mainstream primary school context. This study aimed to investigate the relationship between school climate and efficacy for inclusion and whether this relationship impacts on perceptions of challenging behaviours, further identifying barriers to and supports for efficacious inclusive practice. Fifty-seven probated primary mainstream teachers in the Republic of Ireland responded to online questionnaires exploring perceptions of school climate, teacher efficacy for inclusion and challenging behaviours. Teachers' perceptions of a supportive school climate related positively to their teaching efficacy for inclusion, in turn influencing their ratings of the severity of and their confidence in managing commonly experienced challenging behaviours in inclusive classrooms. Teachers looked within their school for support, few noting Educational Psychologists (EPs) as sources for support. These findings add weight to the importance of understanding the relationship between teachers' perceptions of their school climate and their efficacy for inclusion, addressing the dearth of research in an Irish context. In particular, these findings underline the potential offered by an understanding of teachers' beliefs to inform and enhance the role of EPs in supporting efficacious inclusive practice.