Antineutrophil cytoplasmic autoantibodies (ANCA)-associated vasculitides (AAV) are a group of systemic vasculitis syndromes characterized by inflammation and necrosis of blood vessel walls. Genetic, epigenetic, and environmental factors contribute to the etiology and pathogenesis of AAV. On the basis of currently available clinical and experimental evidence, it is reasonable to believe that, in predisposed patients, different triggers can lead to the production of autoantibodies (ANCA) that, in the context of an inflammatory environment, can cause tissue inflammation and vascular injury. Several different pathways and mechanisms in the pathogenesis of AAV are described in this contemporary review.