Here, we report that miR-125b is upregulated, whereas A20 is downregulated in NPC tissues relative to normal nasopharyngeal mucosa (NNM); miR-125b promotes NPC cell proliferation and inhibits NPC cell apoptosis by targeting A20/NF-κB signaling pathway; A20 inhibits NPC cell proliferation, induces NPC cell apoptosis, and reduces the growth of NPC xenograft tumors. This evidence concerns the gene NFKB1 and nasopharyngeal carcinoma.