In this study, we examine differences in alcohol drinking between first- and second-generation non-European immigrant and native-Swedish adolescents. We also examine whether parental and peer attitudes toward alcohol are associated with the acculturation of drinking habits among adolescents with an immigrant background. The study is cross-sectional and based on a school survey conducted in 2016–2019 in eight municipalities in southern Sweden. The sample consists of 3743 adolescents in year 9 of compulsory education, aged 14–15 years, of which 538 (14.4%) had a non-European immigrant background. Non-European immigrant adolescents reported significantly lower levels of drinking than native-Swedish adolescents. Second-generation immigrants reported a higher level of consumption than first-generation immigrants, and among first-generation adolescents, drinking was more prevalent the longer the adolescents had resided in Sweden, which suggests acculturation of drinking habits. This acculturation is mainly related to changes in peer attitudes toward alcohol. Immigrant adolescents with a longer stay in Sweden reported having friends with more positive attitudes toward alcohol. Among first-generation immigrants, drinking was more common among boys than girls. These differences were primarily found among immigrant adolescents with a relatively short period of residence in Sweden, which suggests that acculturation occurs more quickly among boys than among girls.