Cluster of differentiation 16 (CD16) is a receptor on natural killer cells, neutrophils, monocytes, and macrophages that binds the Fc portion of antibodies to activate these immune cells. CD16 (FcγRIII) is a low affinity Fc receptor that binds to IgG antibodies. Two forms of the receptor, CD16A (FcγRIIIa) and CD16B FcγRII (Ib) are present in natural killer cells, neutrophils, monocytes and activated macrophages.

CD16 staining is useful in the differential diagnosis of hepatosplenic gamma delta T-cell lymphoma and gamma delta T-cell large granular lymphocyte leukemia from mucosal and cutaneous gamma delta T-cell lymphoma. Likely due to dysgranulopoiesis, granulocytes with myelomonocytic leukemia have decreased CD16 expression in comparison to granulocytes with chronic myelogenous leukemia and control bone marrow biopsies.