ABSTRACT Background: To evaluate the impact of medical cannabis laws (MCLs) on health insurance premiums. We study whether cannabis legalization significantly impacts aggregate health insurer premiums in the individual market. Increases in utilization could have spillover effects to patients in the form of higher health insurance premiums. Methods: We use 2010–2021 state-level U.S. private health insurer financial data from the National Association of Insurance Commissioners. We examined changes to individual market health insurance premiums after the implementation of medical cannabis laws. We employed a robust difference-in-differences estimator that accounted for variation in policy timing to exploit temporal and geographic variation in state-level...