This study investigates the relations between teachers' attitudes towards persons with intellectual disability (ID), in-service training on ID, and prior contacts with persons with ID. A sample of Canadian elementary school teachers (N?=?118) completed the Attitudes Toward Intellectual Disability Questionnaire, which measures cognitive, affective and behavioural components of attitudes towards persons with ID. Correlational and multivariate regression analyses were performed. Frequent contacts with persons with ID and experience of including a child with ID increased the likelihood of reporting prior positive contacts with persons with ID. In turn, this was associated with less discomfort towards persons with ID and more willingness towards interactions. In-service training on ID was related to better knowledge of rights and capabilities of persons with ID. Experience of including a child with ID in general education classrooms increased the likelihood to report feeling competent in teaching children with ID, which predicted more willingness to include children with ID.