We study public demand for the extension of public health insurance to psychological services. Previous research neglects the interplay of self‐interest and ideology to explain individuals’ willingness to pay for public mental health care. Relying on an original survey of the Quebec population, we show that support for the extension of mental health insurance is relatively weak on average, but find constituencies of support among the youth, those without private insurance, those with unmet mental health care needs and among left‐wing respondents. Hence, our study contributes to research by mapping the coalitions for and against the extension of public insurance.