Antibody-dependent cellular cytotoxicity (ADCC), also called antibody-dependent cell-mediated cytotoxicity, is an immune mechanism through which Fc receptor-bearing effectors cells can recognize and kill antibody-coated target cells expressing tumor- or pathogen-derived antigens on their surface. Numerous associations between ADCC activity, Fc receptor polymorphisms, and clinical outcomes have been observed in both the settings of vaccination and monoclonal antibody therapy. Here, the effector cells and receptors involved in ADCC are introduced, followed by a description of the four main stages and mechanisms leading to the antibody-dependent effector-mediated killing of the target cell