Suppressor of cytokine signaling 3 (SOCS3 or SOCS-3) is a protein that in humans is encoded by the SOCS3 gene. This gene encodes a member of the STAT-induced STAT inhibitor (SSI), also known as suppressor of cytokine signaling (SOCS), family. SSI family members are cytokine-inducible negative regulators of cytokine signaling. SOCS3 is a conserved gene, found in across the animal kingdom, including Drosophila, chickens, and crocodiles.