Background and AimsOn 1 May 2018, Scotland became the first country in the world to introduce minimum unit pricing (MUP), a strength‐based floor price below which alcohol cannot be sold, across all alcoholic beverages. The legislation contains a sunset clause meaning a comprehensive mixed‐methods evaluation of its impact across a range of outcomes will inform whether it will continue beyond its sixth year. In this study, we assessed the impact of MUP on off‐trade alcohol sales (as a proxy for consumption) after its first year.Design, Setting and ParticipantsControlled interrupted time–series regression was used to assess the impact of MUP on alcohol sales among off‐trade retailers in Scotland in the year after it was introduced, with England and Wales (EW) being the control group. In adjusted analyses, we included household disposable income, on‐trade alcohol sales and substitution between beverage categories as covariates.MeasurementsWeekly data on the volume of pure alcohol sold by off‐trade retailers in Scotland and EW between January 2013 and May 2019, expressed as litres of pure alcohol per adult.FindingsThe introduction of MUP in Scotland was associated with a 3.5% [95% confidence interval (CI) = 2.2–4.9%] reduction in off‐trade alcohol sales per adult after adjustment for the best available geographical control, disposable income and substitution. In unadjusted analysis, the introduction of MUP was associated with a 2.0% (95% CI = 0.4–3.6%) reduction in off‐trade alcohol sales per adult in Scotland. In EW, there was a 2.4% (95% CI = 0.8–4.0%) increase during the same time‐period. The reduction in off‐trade alcohol sales in Scotland was driven by reduced sales of spirits, cider and perry beverage categories.ConclusionThe implementation of minimum unit pricing for alcohol in Scotland in 2018 appears to have been associated with a reduction in off‐trade alcohol sales after its first year.