Risky single-session alcohol consumption or 'binge' drinking is associated with increased health risks and deleterious health, social, and economic outcomes. The aim of this study was to explore the lay causes of excessive alcohol consumption among members of the general public in the UK and Australia. Participants in the UK (N = 133) and Australia (N = 102) completed a network diagram exercise requiring them to indicate the causal relations and the relative strength of the causes among a set of 12 candidate factors (income, age, alcohol availability, drinking culture, low alcohol cost, alcohol advertising, stress, peer pressure, supermarket discount, parental influence, 24-hour opening, boredom) and binge drinking. Findings indicated that the low alcohol cost was the most consistently and strongly factor directly linked to binge drinking by the UK participants. In contrast, Australian participants identified drinking culture and peer pressure as major causes alongside low alcohol cost. While there was consistency in the major perceived cause of binge drinking in the two national groups, some key differences emerged, particularly concerning the role of drinking culture. Current findings may inform the development of preventive measures, health policy, and behavioural interventions with respect to binge drinking.