We examine differences in the prescribing of psychiatric medications to low-income and higher-income children in the Canadian province of Ontario using rich administrative data that includes diagnosis codes and physician identifiers. Our most striking finding is that conditional on diagnosis and medical history, low-income children are more likely to be prescribed antipsychotics and benzodiazepines than higher-income children who see the same doctors. These are drugs with potentially dangerous side effects that ideally should be prescribed to children only under narrowly proscribed circumstances. Low-income children are also less likely to be prescribed SSRIs, the first-line treatment for depression and anxiety conditional on diagnosis. Hence, socioeconomic differences in the prescribing of psychotropic medications to children persist even in the context of universal public health insurance and universal drug coverage.