Food allergy has become a significant public health problem affecting a large number of people worldwide. Maternal obesity causes inflammation and alters the immune system of offspring, which may exacerbate their food allergy. The aim of this study was to determine whether offspring mice born to obese mothers would have more serve reactions to cow’s milk protein-induced food allergy, and further investigate the underlying mechanisms. Female offspring BALB/c mice of mothers with normal and high-fat diets were sensitized with β-lactoglobulin (BLG), respectively. Maternal obesity increased the serum immunoglobulin E and mouse mast cell protease levels, though did not have significant influence on anaphylactic symptom score, core temperature and diarrhea rate of offspring mice after BLG sensitization. Furthermore, maternal obesity led to a lower level of occludin mRNA expression in BLG-sensitized mice. The mice born to obese mothers exhibited increased mRNA expression levels of GATA-3, interleukin (IL)-4 and IL-10 in jejunum after BLG sensitization, indicating maternal obesity intensified Th2-type biased immune responses. In conclusion, maternal obesity exerted exacerbating effects on the responsiveness of their offspring to cow’s milk protein sensitization.