GATA-3 was first cloned as a T cell specific transcription factor in 1991 and its importance in the transcriptional control of T helper type 2 cell (Th2) differentiation was established in the mid to late 90's. A role for GATA-3 during thymic development has long implied by its continuous and regulated expression through out T lineage development, but the absolute requirement for GATA-3 during early T lymphoid commitment/survival previously precluded definitive answers to this question. Several technical breakthroughs have fueled fruitful investigation in recent years and uncovered unexpected and critical roles for GATA-3 in CD4 thymocyte survival, invariant natural killer T cell generation and function, and also in beta selection. Not only does GATA-3 participate in nearly every stage of T cell development from common lymphoid progenitor to Th2, conditional knockout studies have indicated that the influence of GATA-3 also extends beyond the immune system.