Thymic stromal lymphopoietin (TSLP), an IL-7-related cytokine, is widely expressed by epithelial cells in many tissues with different biological effects. Human TSLP (hTSLP) has been shown to play an important role in promoting T cell homeostasis, developing nondeletional central tolerance, amplifying epithelium-induced class switching, inducing atopic diseases and maintaining intestinal noninflammatory environment. Among diverse cells responding to hTSLP, dendritic cells (DCs) are the most obviously characterized target cells. In this review, we attempt to outline an effect of the functional versatility of hTSLP-activated DCs (hTSLP-DCs) on T cells.