Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disorder primarily affecting the joints, leading to inflammation, pain, and progressive joint destruction. It is characterized by synovial hyperplasia, inflammatory cell infiltration, and the production of autoantibodies such as rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs). The etiology of RA involves a complex interplay of genetic, environmental, and immunological factors. Genetic predisposition, particularly the presence of HLA-DRB1 alleles, significantly increases the risk of developing RA. Environmental triggers, such as smoking and infections, may initiate or exacerbate the disease in genetically susceptible individuals.