Abstract Background During the past two decades, alcohol use has decreased among adolescents, but on the contrary, anxiety symptoms have increased (at least among females). These diverging trends set interesting opportunities to examine whether the strength of the well-known correlation/co-occurrence between alcohol use and anxiety has also changed. This study aims to examine changes in the co-occurrence and associations between heavy episodic drinking (HED) and generalized anxiety among adolescents in Finland from 2013 to 2023. Methods Data from the Finnish School Health Promotion Study between 2013-2023 covered 874 110 participants aged 13-20. Generalized anxiety was measured using Generalized Anxiety Disorder Scale (GAD-7) (range 0-21), and heavy episodic drinking was measured as reported heavy drunkenness once a month or more often versus less than once a month. Yearly prevalence estimates of co-occurrence were analyzed for those with moderate to severe anxiety symptoms (>10) and monthly or more frequent HED. Associations between anxiety and HED were analyzed using logistic regression and time-varying effect modelling. Interactions between time and anxiety predicting HED were also considered. Results The moderate to severe anxiety symptoms increased from 10.7% to 20.9% and HED decreased from 18.0% to 11.8% between 2013 and 2023. The proportion of those with both HED and moderate to severe anxiety increased from 2.9% in 2013 to 3.6% in 2023. The association between anxiety symptoms and HED was stable during the study period, with odds ratios ranging between 1.06 and 1.07. Conclusions During the past decade, diverging trends in generalized anxiety symptoms and heavy episodic drinking have not changed the association between them. The proportion of adolescents with these co-occurring health concerns has increased in females. This calls for continuous efforts to strengthen the integration of mental health and substance use prevention and services. Key messages • The association between generalized anxiety and heavy episodic drinking has not changed in adolescents in Finland between 2013 and 2023. • The proportion of those with both moderate to severe anxiety symptoms and heavy episodic drinking has increased in females and remained stable in males during the past decade (2.9% - 3.6%).