Innate lymphoid cells (ILCs) and related natural killer (NK) cells have garnered considerable interest due to their roles in immune defense and tissue homeostasis. Our current understanding of how these cells function in immune responses has been greatly facilitated by our extensive knowledge of T cell biology. Established models of T cell differentiation have provided the conceptual basis for a classification of ILCs and NK cells as innate homologues of adaptive T helper cells and cytotoxic T cells, respectively. Furthermore, activation of mature NK cells and ILCs finds parallels with known regulatory mechanisms operating within the T cell system. I will extend this ‘T cell perspective’ to discuss the developmental pathways that generate functionally distinct ILC subsets in the context of local tissue environments.