Evidence about the role of nutritional factors and microbiota in autoimmune diseases, and in rheumatoid arthritis (RA) in particular, has grown in recent years, however many controversies remain. The aim of this review is to summarize the role of nutrition and of the intestinal microbiota in the development of RA. We will focus on selected dietary patterns, individual foods and beverages that have been most consistently associated with RA or with the occurrence of systemic autoimmunity associated with RA. We will also review the evidence for a role of the intestinal microbiota in RA development. We propose that diet and digestive microbiota should be considered together in research, as they interact and may both be the target for future preventive interventions in RA.