Previous research has identified the importance of teacher attitudes and self-efficacy in supporting inclusive education. This study involved a multi-national exploration of a further dimension of inclusive education, collective efficacy, through the testing of a new tool, the Teacher Efficacy for Inclusive Practice-Collective (TEIP-C) Scale. The study also aimed to investigate whether teacher attitudes, self-efficacy, collective efficacy and intention to teach in inclusive classrooms differ across countries. Participants included 1,523 teachers from Canada, Greece, Italy and Switzerland. Results suggested a two-factor structure for the TEIP-C, Engagement, and Inclusive Pedagogies, with strong internal consistency for the scale. Several differences across countries were identified, with teachers from Italy reporting more positive attitudes towards inclusion and a greater intention to teach in inclusive classrooms. Implications of the study in terms of further strengthening inclusive practice are discussed.