Atrial fibrillation (AF) is a prevalent arrhythmia associated with substantial morbidity, mortality and costs. Available management strategies generally have limited efficacy and are associated with potential adverse effects. In part, the limited efficacy of approaches to managing AF reflect an incomplete understanding of the biological mechanisms underlying the arrhythmia, and only a partial understanding of how best to individualise management. Over the last several decades, a greater understanding of genome biology has led to recognition of a widespread genetic susceptibility to AF. Through genome-wide association studies, at least 30 genetic loci have been identified in association with AF, most of which implicate mechanisms not previously appreciated to be involved in the development of AF. We now recognise that AF is a polygenic condition, yet a great deal of work lies ahead to better understand the precise mechanisms by which genomic variation causes AF. Understanding the genetic basis of AF could provide a better understanding of AF mechanisms and cardiovascular biology, inform the management of patients through risk-guided approaches and facilitate the development of novel therapeutics.