Nuclear factor kappa-B (NF-κB) signaling-mediated inflammation contributes greatly to the pathogenesis of periodontitis. Neddylation, a ubiquitin-like posttranslational modification, is known to regulate NF-κB signaling. DCUN1D1 (defective in cullin neddylation 1 domain containing 1) is a critical factor in neddylation and has been shown to regulate NF-κB activation. However, the previse roles of DCUN1D1 in periodontitis are not fully elucidated. To explore the roles of DCUN1D1 in periodontitis, the expression of DCUN1D1 was measured in gingival tissues of patients with periodontitis. We inhibited DCUN1D1 by siRNA knocking down or using inhibitor in gingival fibroblasts and the lipopolysaccharides (LPS)-induced expression of IL-6 and TNF-α, and activation of NF-κB were measured. The expression of DCUN1D1 was increased in gingival tissues of patients with periodontitis. Knocking down or inhibiting DCUN1D1 suppressed LPS-induced production of IL-6 and TNF-α, decreased NF-κB activity, and inhibited LPS-induced activation of NF-κB. Inhibiting DCUN1D1 ameliorates periodontitis by suppressing NF-κB signaling.