Rheumatoid arthritis (RA) is a progressive autoimmune disease leading to structural and functional joint damage and, eventually, to physical disability. The pathogenesis of the disease is highly complex and involves interactions between fibroblast-like synoviocytes (FLSs) and immune cells, which stimulate the secretion of pro-inflammatory factors, leading to chronic inflammation. In recent years, studies have demonstrated the importance of epigenetics in RA. Specifically, epigenetic alterations have been suggested to serve as diagnostic and treatment biomarkers, while epigenetic mechanisms are thought to be involved in the pathogenesis of RA. Epigenetic regulators coordinate gene expression, and in the case of inflammatory diseases, they regulate the expression of a broad range of inflammatory molecules. In this review, we discuss current evidence on the involvement of DNA and RNA methylation in RA.