Understanding how knowledge of alcohol-related harms relates to policy support can inform strategies to increase acceptance of alcohol policies. This study examines the relationship between the two across five EU countries. Online survey measuring knowledge of alcohol-related health consequences and alcohol policy support was conducted in October-November 2024 (N = 3620). Associations were analysed using adjusted linear regression models. Support for alcohol control measures was largely consistent across the countries and was lowest for increasing alcohol price and highest for implementing drink-driving measures. Factor analysis of 15 policy items showed four factors: Supportive and Educational interventions, Marketing and Youth Protection policies, Point of Sale and Display Regulation policies and Pricing and Physical Availability control policies. After adjusting for sociodemographic characteristics and alcohol consumption patterns, knowledge of alcohol causing cancer was positively associated with support for Point of Sale and Display Regulation (β = 0.18, 95% CI: 0.11 to 0.25) and Pricing and Physical Availability control policies (β = 0.12, 95% CI: 0.05 to 0.19). Belief that wine benefits heart health was negatively associated with support for Marketing and Youth Protection policies (β = -0.09, 95% CI: -0.16 to -0.02) and Pricing and Physical Availability control policies (β = -0.11, 95% CI: -0.18 to -0.04). This study replicates the previous findings demonstrating the relationship between cancer knowledge and support for population-level alcohol policies in the European context. Interventions aimed at increasing this knowledge should be considered a critical foundation for effective alcohol control efforts, as informed publics are more likely to support and engage with population-level measures.