Adipose-derived mesenchymal stem cells (ADMSCs) possess immunomodulation property, yet their therapeutic potential in asthma is unclear. This study aimed to explore the effects of ADMSCs on airway hyperresponsiveness and inflammation in ovalbumin (OVA)-induced asthma models. The underlying mechanism(s) was also examined. BALB/c mice were sensitized with OVA on days 0, 7, and 14, followed by 8-week OVA challenge from day 22. ADMSCs were injected via tail vein on day 21. Animals were measured for airway responsiveness, lung pathology, IgE and cytokine levels in serum, cell composition in bronchoalveolar lavage fluid (BALF), gene expression in the lung, and regulatory T cells (Tregs). We found that delivery of ADMSCs decreased airway responsiveness and eosinophil counts in BALF and reduced infiltration of inflammatory cells and number of mucus-expressing goblet cells in the lung in OVA-challenged mice. OVA-evoked elevation of serum IgE levels and alteration of cytokine production in serum and BALF was significantly prevented by ADMSCs. In addition, administration of ADMSCs impaired the regulation of lung IL-10, Foxp3, IL-17, and RORγ expression by OVA challenge and restored the percentage of CD4+CD25+Foxp3+ Tregs in the spleen. In conclusion, ADMSCs confer protection against OVA-induced airway hyperresponsiveness and inflammation, which is associated with induction of Tregs and restoration of immune homeostasis. These findings suggest that ADMSCs may have therapeutic implications for allergic asthma.