Background: Few studies have examined attitudes that may promote the social inclusion of persons with an intellectual disability (ID) among health care providers (HCPs). Yet these attitudes could impact the accessibility and quality of services provided to this population, as well as the general attitudes of HCPs. The objectives of this study were to (1) examine HCPs' pro-inclusion attitudes toward people with ID, (2) compare these to the general population's attitudes and (3) examine how HCPs' attitudes vary as a function of their socio-demographic characteristics. Method: The "Attitudes Toward Intellectual Disability Questionnaire" was administered to 367 HCPs and a representative sample of the Québec population (N = 1605). Results: Results indicated that at least half of HCPs displayed positive attitudes, that is, attitudes that are compatible with notions of social inclusion and equal rights, toward individuals with ID. Positive attitudes were less frequently observed for the "Interaction" and the "Sensitivity or tenderness" factors measured by the "Attitudes Toward Intellectual Disability Questionnaire." In comparison with the general population, HCPs exhibited more positive attitudes on the "Knowledge of causes" and "Sensitivity or tenderness" factors and less positive attitudes on the "Interaction" factor. HCPs who regarded themselves as more knowledgeable about ID and those who reported higher quality contacts or interactions with persons with ID expressed attitudes that were more favourable toward social inclusion. Conclusions: In addition to providing general knowledge about ID and the specific health care needs of individuals with ID, training programmes should also promote interactions with this population. Further studies are needed to document HCPs' pro-inclusion attitudes toward people with ID and to assess the impact of interventions on these attitudes.