Our data demonstrate that miR-125b regulates NPC cell proliferation and apoptosis by targeting A20/NF-κB signaling pathway, and miR-125b acts as oncogene, whereas A20 functions as tumor suppressor in NPC, highlighting the therapeutic potential of miR-125b/A20/NF-κB signaling axis in the NPC. The gene discussed is TNFAIP3; the disease is neoplasm.