As the number of students with Autism Spectrum Disorder (ASD) increases, so does the need for teacher training about inclusive education. We adapted an online training to provide pre-service teachers with strategies to integrate students with ASD into the classroom and evaluated it in two culturally diverse contexts. Students majoring in Education from the United States (Georgia; n = 84) and Canada (Québec; n = 117) completed the training and filled out pre- and post-training questionnaires. Initial attitudes toward inclusion were significantly more positive in Georgia than Québec. Participation in the training was associated with improved attitudes towards inclusion across both contexts and with improved ASD teaching self-efficacy and knowledge in Québec. Increased self-efficacy in Georgia was associated with a social desirability bias. This study demonstrates that a brief online training can promote positive attitudes toward inclusion across contexts.