Abstract Background Adolescents and young adults are a group particularly vulnerable to the effects of alcohol consumption. In Portugal, legislative changes in 2013 and 2015 prohibited the sale of alcoholic beverages to under-18s. This study aimed, first, to evaluate the impact of these policy shifts on the perceived access to alcohol among Portuguese adolescents, and second, to assess the different impacts across gender and socioeconomic strata. Methods Data from the ESPAD survey, spanning 1995-2019, was used. A quasi-experimental difference-in-differences study design was employed, using Finland, Norway, and Sweden as controls. The perceived access to beer, wine, and spirits among 16-year-old adolescents was used as outcomes, adjusted for gender and parental education. Results were also stratified by gender and by parental education status. Results After the increase in the minimum age for alcohol sales, there was a higher perceived easiness of access to beer (coef=0.018, p = 0.001) and a decline in spirits (coef=-0.088, p = 0.022), with no changes in wine. Male adolescents exhibited a decrease in the perception of access to spirits (coef=-0.100, p = 0.007) and wine (coef=-0.049, p = 0.049), while changes in the perception of access to beer were non-significant. Similar patterns were observed in female adolescents, yet non-significant for wine or spirits. These positive impacts on beer and negative impacts on spirits were observed in the different socioeconomic groups; wine was the exception, with only the highest-education group showing a decrease in the perception of access (coef=-0.056, p = 0.011). Conclusions In this study, the effect of raising the minimum age for alcohol sales in Portugal varied according to the alcoholic beverage, gender, and, for wine, according to the socioeconomic group. These findings suggest limitations in the policy’s effectiveness and equity. Future research should delve into the underlying causes to optimize health-promoting policies. Key messages • Portugal’s alcohol policy changes led to differential impacts on the perception of access to alcohol, with an impact in higher alcohol content beverages. • The impact of alcohol policy changes also differed across gender and socioeconomic status, with a stronger effect on male adolescents and higher socioeconomic strata.