This is the first large-scale, quantitative study of the evaluative dimensions and potential predictors of Quebec-based parents' attitudes towards childhood multilingualism. Such attitudes are assumed to constitute a determinant of parental language choices, and thereby influence children's multilingual development. The newly-developed Attitudes towards Childhood Multilingualism Questionnaire was used to gather data from 825 participants raising an infant/toddler aged 0-4 years with multiple languages in the home. The results revealed three separate dimensions: status and solidarity (the same dimensions found in attitudes towards individual languages) as well as cognitive development (not previously attested as a separate dimension). Participants' approach to promoting multilingualism (specifically, whether they used the one-person-one-language-approach) and the combination of languages transmitted (specifically, whether this included a heritage language) correlated significantly with parental attitudes towards childhood multilingualism. Parents' linguistic background and location within Quebec were not significant predictors of attitudes. The paper discusses implications and directions for further research.