Natural killer (NK) cells are crucial to mounting an effective immune response. They have a significant role in cancer immunosurveillance and function as a bridge between innate and adaptive immunity. However, until recently, surprisingly little was known about the molecular basis of NK cell development as compared to the impressive body of knowledge on B- and T-cell development. Here we outline the key transcription factors known to influence NK cell development and at what stages they function. The recent progress in understanding allows us to speculate on the nature of the network of interactions between transcription factors that ultimately facilitate the production of mature functional NK cells.