Driven by a joint objective to better understand and reduce the spread of misinformation with insights and tools from behavioural science, the OECD, in partnership with behavioural science experts from the Canadian Privy Council's Office's Impact Canada (IIU) and from the French Direction interministérielle de la transformation publique (DITP), launched a first-of-its-kind international collaboration. This study tested the impact of two behaviourally-informed interventions on intentions to share true and false news headlines about COVID-19 on social media: an attention accuracy prompt and a set of digital media literacy tips. The policy paper outlines key behavioural insights gained to help improve policy responses and stop the spread of mis- and dis-information.