Cells that belong to the family of innate lymphoid cells (ILCs) not only form a first line of defense against invading microbes, but also play essential roles in tissue remodeling and immune pathology. Rorγt+ ILCs, producing the cytokines IL-22 and IL-17, include lymphoid tissue inducer (LTi) cells which are critical for the formation of lymphoid structures. Recently another ILC subset has been identified, which is dependent on RORα for its development and is dedicated to the production of the Th2 cytokines IL-5 and IL-13. These ILCs have been termed type 2 ILCs. All ILC subets are considered to belong to the same family that also includes natural killer cells because they all rely on the common γ-chain (γc) of the IL-2 receptor for their development and function, share a lymphoid morphology and depend on the transcriptional repressor Id2 for their development. Other transcription factors, including Notch, and the aryl hydrocarbon receptor (AhR) in RORγt+ ILCs and GATA3 in type 2 ILCs, also play roles in the development, survival, and function of these ILC subpopulations. Here we review the current knowledge with regard to the transcription factors involved in the development and functions of ILCs.