The modulation of adhesion molecule expression and the reduction of aberrant leukocyte adhesion to the endothelium are attractive approaches for treating inflammation-related vascular complications, including atherosclerosis. Dioscin has a variety of biological activities including anti-inflammatory activity. However, the molecular mechanisms behind dioscin's anti-inflammatory effects are not fully understood. In this study, we investigated the molecular mechanism involved in the effects of dioscin on inflammatory mediators in tumor necrosis factor-α (TNF-α)-stimulated human umbilical vein endothelial cells (HUVECs). In vitro, dioscin decreased monocyte adhesion to TNF-α-treated HUVECs by reducing vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) expression and inhibiting endothelial lipase (EL) expression in TNF-α-treated HUVECs and macrophages by blocking the nuclear factor-κB (NF-κB) pathway. Thus, dioscin might inhibit inflammation by interrupting the NF-κB signaling pathway and could potentially contribute to treatments for inflammatory diseases and atherosclerosis.