Over the past 15 years, genome-wide association studies (GWASs) have identified more than 2,900 genetic loci associated with adiposity traits. The majority of these loci were discovered through large-scale GWAS meta-analyses for body mass index (BMI) and waist-to-hip ratio (WHR), mostly in adults and in European ancestry populations. However, some gene discovery efforts have focused on non-European ancestry populations, more refined adiposity traits, childhood and adolescent populations, and rare coding variants. Loci associated with overall obesity implicate pathways that act in the brain, whereas loci associated with body fat distribution point to pathways involved in adipocyte biology, lipolysis, glucose metabolism, and insulin resistance. In-depth functional follow-up analyses have been performed for a fraction of GWAS loci, and we are slowly expanding our understanding of the biology that underlies obesity and fat distribution. However, many more obesity-associated loci are waiting to be translated. With the increasing number of discoveries, there is a growing interest in using genetic information to predict who is at risk for developing obesity. However, prediction models that are solely based on genetic information show poor predictive accuracy. Given that both genetic and nongenetic factors contribute to body weight, effective models to predict obesity will have to include genetic and nongenetic factors.