In this study, we investigated the effects of oral ingestion of Lactobacillus crispatus KT-11 strain (KT-11) on the immune response in an allergic rhinitis mouse model, ovalbumin (OVA)-sensitized BALB/c mice. Sneezing activity in mice that were administered a KT-11-supplemented diet was significantly lower than that in mice administered a KT-11-free diet (control diet) at age 11 weeks. We found that serum OVA-specific immunoglobulin E (IgE) levels and total number of interleukin (IL)-4(+) CD4(+) spleen cells in mice that were administered a KT-11-supplemented diet were significantly lower than in mice administered a control diet. The ratio of spleen interferon-γ(+) CD4(+) /IL-4(+) CD4(+) cells was higher in the mice administered the KT-11-supplemented diet compared to that in mice administered the control or L. rhamnosus GG-supplemented diet. In contrast, the number of CD11b(+) CD80(+) and FcεRIα(+) CD117(+) cells was significantly lower in mice administered the KT-11-supplemented diet. These results suggested that KT-11 reduced OVA-induced allergic symptoms in BALB/c mice via the adjustment of the T helper type 1/T helper type 2 balance, and a decrease in the number of antigen-presenting cells and high affinity IgE receptor-positive mast cells.