This provincial case study, one of seven conducted as part of a national research program on healthcare supply chain management during COVID-19, focuses on Ontario. The context of significant restructuring of health organizations and regions in Ontario challenged the province’s capacity to respond to COVID-19. A complex leadership structure, led by political leaders, with limited healthcare supply chain expertise at decision-making tables and a prioritization of “hospitals first” early in the first wave were described as challenges Ontario faced in managing the pandemic. A lack of supply chain digital infrastructure—and consequently, lack of available data—meant informed decision-making regarding supply utilization and demand forecasting was not possible. The Ontario case presents key lessons learned regarding the unintended consequences of lack of supply chain coordination across organizations, and the prioritization of hospitals and allocation strategies on Canada’s most vulnerable population segments.