Rheumatology (Greek ῥεῦμα, rheûma, flowing current) is a branch of medicine devoted to the diagnosis and therapy of rheumatic diseases. Physicians who have undergone formal training in rheumatology are called rheumatologists. Rheumatologists deal mainly with immune-mediated disorders of the musculoskeletal system, soft tissues, autoimmune diseases, vasculitides, and heritable connective tissue disorders.

Many of these diseases are now known to be disorders of the immune system. Rheumatology is considered to be the study and practice of medical immunology.

Beginning in the 2000s, the incorporation of drugs called the biologics (which include inhibitors of TNF-alpha, certain interleukins, and the JAK-STAT signaling pathway) into standards of care is one of the paramount developments in modern rheumatology