In the present study, an Inclusive Engagement Scale was developed to measure the engaging behaviors of mainstream classroom teachers in elementary schools as they communicate with children in a manner that reflects the children's intellectual disabilities to promote inclusive education and to explore factors influencing inclusive engagement. First, 2 preliminary research studies were conducted in order to develop a draft of the Inclusive Engagement Scale. Using those data, items in the proposed scale were evaluated and a hypothetical model for factors influencing inclusive engagement was created. Then, a web-based survey was conducted, using the newly developed scale, which obtained 196 valid responses from mainstream classroom teachers (131 men, 65 women) in elementary schools. Factor analysis of the Inclusive Engagement Scale identifıed 3 factors: "conveying instructions to children with intellectual disabilities," "understanding children with intellectual disabilities," and "independent/normalizing engagement." All 3 factors showed high internal consistency, thereby supporting reliability. Moreover, criterion-related validity was supported by a moderate positive correlation with an existing scale with which association was expected. In the examination of factors that influence inclusive engagement, previous experience with special education was set as the fırst level; self-help resources and support resources, the second level; current relationship formation, the third level; and inclusive engagement, the fourth level. The results of a path analysis under these conditions indicated specifıc effects from each level.