BACKGROUND AND AIMS: Many countries have legalised gambling, negatively impacting public health. Stakeholders are particularly concerned about online gambling advertising harming young adults. The Netherlands has legalised offline and online gambling, but subsequently introduced restrictions on advertising. Specifically, advertisements must not target young adults aged between 18 and 23. The EU Digital Services Act requires major social media platforms to publish databases of all paid adverts shown and disclose which demographic groups were the intended targets and how many users were eventually reached. We assessed whether Dutch gambling ads on social media illegally targeted under-24s.

METHODS: We systematically collected recent advertisements (N = 277) published by both online and offline Dutch gambling licensees and associated demographic targeting and reach data using Meta's Ad Library. We then assessed whether the age range of users targeted by those ads included prohibited targets.

RESULTS: The compliance rate was 92.7% for online gambling licensee ads, but only 70.2% for offline licensee ads.

DISCUSSION: A significant minority of gambling ads illegally targeted Dutch young adults under 24. Whilst compliance is relatively high, building some confidence, the regulator must robustly enforce the rule against all licensees. Meta should adopt platform-level changes to reduce compliance friction.

CONCLUSIONS: Prohibiting gambling adverts from targeting vulnerable demographics using technology is a practicable policy. Legally mandated data access can facilitate public scrutiny of policy implementation, enhancing accountability. Other countries may benefit from emulating these Dutch gambling advertising restrictions and EU advertising transparency regulations, better protecting vulnerable consumer demographics and enabling local research.