Asthma is more common in females than males after adolescence. However, the mechanism of the sex bias in the prevalence of asthma remains unknown. To test whether sex steroid hormones have some roles in T cells during development of asthma, we analyzed airway inflammation in T cell-specific androgen receptor (AR)- and estrogen receptor (ER)-deficient mice. T cell-specific AR-deficient male mice developed severer house dust mite-induced allergic airway inflammation than did control male mice, whereas T cell-specific ERα- and ERβ-deficient female mice exhibited a similar degree of inflammation as for control female mice. Furthermore, administration of dihydrotestosterone reduced cytokine production of Th2 cells from control, but not AR-deficient, naive T cells. Transfer of OT-II transgenic AR-deficient Th2 cells into wild-type mice induced severer allergic airway inflammation by OVA than transfer of control Th2 cells. Gene expression profiling suggested that the expression of genes related with cell cycle and Th2 differentiation was elevated in AR-deficient Th2 cells, whereas expression of dual specificity phosphatase (DUSP)-2, a negative regulator of p38, was downregulated. In addition, a chromatin immunoprecipitation assay suggested that AR bound to an AR motif in the 5' untranslated region of the Dusp2 gene in Th2 cells. Furthermore, the Dusp2 promoter with a wild-type AR motif, but not a mutated motif, was transactivated by dihydrotestosterone in a reporter assay. Finally, forced expression of DUSP-2 by retrovirus vector reduced IL-4 expression in Th2 cells. Thus, these results suggest that androgen signaling suppresses cytokine production of Th2 cells by inducing DUSP-2, explaining, in part, the sex bias of asthma after adolescence.