Upon stimulation by environmental signals, T lymphocytes develop an intricate set of signal-dependent responses including remodeling of the actin cytoskeleton, the development of cellular polarity, the initiation of second-messenger cascades, entry into cell cycle, differentiation and effector function. The integration of TCR and costimulatory signaling is critical to the successful initiation of the T cell activation program, and the serine/threonine kinase PKCtheta is an important site of signal integration in the process of T cell activation. We provide an overview of T cell signaling, and then go on to assess our understanding of the regulation of PKCtheta activity, its target proteins and its role in T cell activation and the production of T cell survival factors such as IL-2.