The aim of this study was to investigate the effect of Lactobacillus (L.) acidophilus ATCC 4356 on the progression of atherosclerosis in Apoliprotein-E knockout (ApoE−/−) mice and the underlying mechanisms. Eight week-old ApoE−/− mice were treated with L. acidophilus ATCC 4356 daily for 12 weeks. The wild type (WT) mice or ApoE−/− mice in the vehicle group were treated with saline only. Body weights, serum lipid levels, aortic atherosclerotic lesions, and tissue oxidative and inflammatory statuses were examined among the groups. As compared to ApoE−/− mice in the vehicle group, ApoE−/− mice treated with L. acidophilus ATCC 4356 had no changes in body weights and serum lipid profiles, but showed decreased atherosclerotic lesion size in en face aorta. In comparison with WT mice, ApoE−/− mice in the vehicle group showed higher levels of serum malondialdehyde (MDA), oxidized low density lipoprotein (oxLDL) and tumor necrosis factor-alpha (TNF-α), but lower levels of interleukin-10 (IL-10) and superoxide dismutase (SOD) activities in serum. Administration of L. acidophilus ATCC 4356 could reverse these trends in a dose-dependent manner in ApoE−/− mice. Furthermore, ApoE−/− mice treated with L. acidophilus ATCC 4356 showed an inhibition of translocation of NF-κB p65 from cytoplasm to nucleus, suppression of degradation of aortic IκB-α, and improvements of gut microbiota distribution, as compared to ApoE−/− mice in the vehicle group. Our findings suggest that administration of L. acidophilus ATCC 4356 can attenuate the development of atherosclerotic lesions in ApoE−/− mice through reducing oxidative stress and inflammatory response.