Activation of NF-κB transcription factors by receptors of the innate or adaptive immune system is essential for host defense. However, after danger is eliminated, NF-κB signaling needs to be tightly downregulated for the maintenance of tissue homeostasis. This review highlights key negative regulatory principles that affect the amount, localization or conformational properties of NF-κB-activating proteins to attenuate the NF-κB response. These mechanisms are needed to prevent inflammation, autoimmune disease and oncogenesis.