Objective: Cross-sectoral alcohol policy is recommended to reduce youth alcohol consumption, but little evidence is available on its effectiveness. Therefore, we examined whether regions and municipalities in the Dutch province of Noord-Brabant with stronger cross-sectoral alcohol policy showed larger reductions in alcohol consumption among adolescents aged 12-15. Method: Strong regional cross-sectoral alcohol policy was defined as participation in a regional alcohol prevention program. Strong municipal cross-sectoral alcohol policy was operationalized by measures on (a) sector variety: involvement of different policy sectors, and (b) strategy variety: formulation of different policy strategies. Relevant data from policy documents were searched for on the Internet. Data on trends in alcohol consumption were extracted from the 2007 and 2011 cross-sectional Youth Health Monitor that includes a random subset of adolescents aged 12-15 (n = 15,380 in 2007 and n = 15,437 in 2011). We used multilevel regression models. Results: Two of the three regions in which municipalities participated in a regional alcohol prevention program showed a larger reduction in weekly drinking than the region in which municipalities did not participate (-12.2% and -13.4% vs. -8.3%). Municipalities with strong compared to weak sector variety showed a larger increase in adolescents' age at consuming their first alcoholic drink (0.63 vs. 0.42 years). Municipalities with strong strategy variety showed a decrease (-3.8%) in heavy weekly drinking, whereas those with weak variety showed an increase (5.1%). Cross-sectoral alcohol policy did not affect trends in other alcohol outcomes. Conclusions: Our results suggest that strong cross-sectoral alcohol policy may contribute to reducing some aspects of youth alcohol consumption. Monitoring policy implementation is needed to assess the full impact.