Autism spectrum conditions (ASCs) are neurodevelopmental in origin and entail social-communication disability alongside unusually narrow interests and difficulties adjusting to unexpected change. The cause of ASCs is complex due to the interplay of an array of genetic and environmental factors. Although ASCs are known to be highly heritable, genetic sequencing and association studies have identified only a fraction of the total number of genes thought to be associated with the condition. Nevertheless, neither genetic components nor environmental factors have been able to elucidate the pathophysiology of nonsyndromic ASCs. Recently there has been a paradigm shift in autism research toward investigating how environment mediates gene expression subsequently affecting biological pathways crucial for brain development. In this chapter, we discuss the key epigenetic mechanisms, such as DNA methylation and histone modifications, as potential contributors to the etiopathogenesis of ASCs. We also highlight some of the risk factors affecting autism epigenetics, the limitations of current research, and the implications for future work.