INTRODUCTION: Traditionally, alcohol use and related harms are more prevalent in males than females. However, there is emerging evidence that the epidemiology of alcohol use and harms is changing with females catching up to their male counterparts. If this is true then a reconceptualization of prevention, early intervention and treatment is required. We aim to systematically summarise the literature on sex differences over time in key indicators of alcohol epidemiology (lifetime use, binge drinking, alcohol dependence). METHODS: A systematic review was carried out. Studies were assessed in terms of methodological rigour and ranked according to the strength of evidence. Extracted data were mapped onto five-year birth cohorts dating from 1895-1990. Meta-analytic techniques were used to summarise the estimates. RESULTS: Final estimates were derived from 80 studies across 55 countries. RESULTS indicated a closing of the gender gap across most alcohol epidemiology indicators with the most recent estimates in some countries indicating equal rates amongst men and women. CONCLUSION: Synthesis of data across the world suggests that the traditional gender gap in alcohol use and alcohol-related harms is closing and has, in some countries, closed completely. A discussion of suggested social/cultural/attitudinal reasons for this trend will be presented. Language: en