Minimum legal age laws and perceived access to cigarettes, e-cigarettes, and other substances among youth in Canada, England, and the United States: 2017-2021

•Youth's perceived access to substances was examined in Canada, England, US, 2017-2021.•Minimum legal age (MLA) was strongly associated with perceived ease of access.•Fewer youth in the US (MLA 21) reported easy access to tobacco vs Canada and England (MLA 18).•Ease of accessing tobacco decreased after minimum legal age increased to 21 in the US.•Perceived easy access to cannabis was greater in Canada vs the US and England. Minimum legal age (MLA) restrictions are a core policy to reduce youth use of tobacco, e-cigarettes, and other substances. We examined trends in perceived ease of access to tobacco and other substances across three countries with differing MLA policies, including the United States (US), which increased the federal MLA for tobacco products from 18 to 21 in 2019. Repeat cross-sectional data were analyzed from seven waves of the International Tobacco Control (ITC) Youth Tobacco and Vaping Survey conducted between 2017 and 2021. Online surveys were conducted with non-probability samples of 91,647 youth aged 16-19 in Canada, England, and the US. Regression models were used to examine differences in perceived ease of accessing each of 7 substances (analyzed as “very easy” or “fairly easy” versus else), and differences between countries and over time (including before and after any MLA changes) for cigarettes, e-cigarettes, cannabis, and alcohol; additional models examined sub-national variation in MLA. Perceived access varied by substance and across countries: in August/September 2021, perceived ease of accessing cigarettes and e-cigarettes was greater in Canada where MLA was 18-19 (61.7% cigarettes, 66.4% e-cigarettes) and England where MLA was 18 (66.9%, 69.6%), compared to the US where MLA was 21 (48.0%, 60.9%; p