Adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin, play important roles in the initial stage of atherosclerosis. Cryptotanshinone (CPT), a natural compound isolated from Salvia miltiorrhiza Bunge, exhibits anti-atherosclerotic activity although the underlying mechanisms remain elusive. In this study, the protective effect of CPT against oxidized low-density lipoprotein (ox-LDL)-induced adhesion molecule expression was investigated in human umbilical vein endothelial cells. Ox-LDL significantly induced ICAM-1, VCAM-1, and E-selectin expression at the mRNA and protein levels but reduced eNOS phosphorylation and NO generation, which were reversed by CPT pretreatment. Sodium nitroprusside, a NO donor, N-acetyl-L-cysteine (NAC), a reactive oxygen species (ROS) scavenger, and BAY117082, a NF-κB inhibitor, inhibited ox-LDL-induced ICAM-1, VCAM-1, and E-selectin expression. Ox-LDL-induced ROS production was significantly inhibited by CPT and NAC. Furthermore, ox-LDL activated the NF-κB signaling pathway by inducing phosphorylation of IKKβ and IκBα, promoting the interaction of IKKβ and IκBα, and increasing p65 nuclear translocation, which were significantly inhibited by CPT. In addition, CPT, NAC, and BAY117082 inhibited ox-LDL-induced membrane expression of ICAM-1, VCAM-1, E-selectin, and endothelial–monocyte adhesion and restored eNOS phosphorylation and NO generation. Results suggested that CPT inhibited ox-LDL-induced adhesion molecule expression by decreasing ROS and inhibiting the NF-κB pathways, which provides new insight into the anti-atherosclerotic mechanism of CPT.