Nuclear factor kappa B (NF-kappa B) is a family of inducible transcription factors that plays a vital role in different aspects of immune responses. NF-kappa B is normally sequestered in the cytoplasm as inactive complexes via physical association with inhibitory proteins termed I kappa Bs. In response to immune and stress stimuli, NF-kappa B members become activated via two major signaling pathways, the canonical and noncanonical pathways, and move to the nucleus to exert transcriptional functions. NF-kappa B is vital for normal immune responses against infections, but deregulated NF-kappa B activation is a major cause of inflammatory diseases. Accumulated studies suggest the involvement of NF-kappa B in the pathogenesis of renal inflammation caused by infection, injury, or autoimmune factors. In this review, we discuss the current understanding regarding the activation and function of NF-kappa B in different types of kidney diseases.