Using nationally representative cross-sectional survey data from 2019, this article reports that Canadians generally overestimate the number of refugees and asylum-seekers coming into the country but are comparatively less prone to overestimating the overall number of immigrants. Canadians also rely on mental images about the reasons for immigrating to Canada that diverge from the realities of Canada's immigration program. The authors document how reliance on these numbers and images is driven by the type of media consumed, feelings of threat, and individual-level characteristics of Canadians. In doing so, this article demonstrates that mental images strongly influence Canadians’ attitudes toward immigration; numerical estimates also matter, but less so.