Background Ontario, Canada prohibited menthol tobacco product sales beginning 1 January 2017. We measured retail sales of menthol cigarettes and possible substitute products before and after policy implementation in Ontario.

Methods We licensed retail scanner data for tobacco product sales in Ontario and British Columbia (BC), a comparison province without a menthol tobacco policy at that time. We assessed changes in per capita unit sales (per 1000 people) from pre-policy (January–June 2016) to post-policy (January–June 2017) periods. Classification of cigarettes as menthol or non-menthol, or having menthol-suggestive descriptors (‘green’, ‘blue’, ‘silver’ and ‘fresh’), was based on scanner data.

Results Ontario menthol cigarette sales decreased 93%, from 596 to 40 packs per capita compared with a 2% decrease (696 to 679 packs per capita) in BC. Menthol capsule cigarette sales remained low in Ontario (<1% of total cigarette sales) but rose sixfold in BC. Although cigar sales data were unavailable, substitution appeared minimal; sales of non-menthol cigarettes increased 0.4% in Ontario (11 470 to 11 519 packs per capita) while vaping product sales decreased. Ontario had a larger increase in sales of cigarettes with menthol-suggestive descriptors (11% increase) than BC (3% increase). In Ontario, nearly all (>99%) pre-policy sales of cigarettes with ‘green’ menthol-suggestive descriptors were menthol cigarettes, but post-policy, 94% of ‘green’ cigarettes sold were non-menthol.

Conclusions Ontario’s menthol policy was associated with a decrease in retail sales of cigarettes classified as menthol, with little evidence of product substitution. Understanding changes in sales of cigarettes with menthol-suggestive descriptors would be informative.