T cells are typically considered to be cells that recognize peptide antigens presented by MHC class I or II. However, it is increasingly clear that many T cells do not fit this description. These are sometimes referred to as innate-like T cells. The vast majority of studies into innate-like T cells have focused on one particular subset, typically known as ‘invariant’ Natural Killer T (NKT) cells or Type-1 NKT cells. These express an invariant TCR-ɑ chain (Vɑ24-Jɑ18) and recognise a glycolipid antigen known as ɑ-Galactosylceramide (ɑ-GalCer). However, there are many different types of lipid antigens including foreign and self-lipids, that can be presented by CD1d (an MHC class-I-like molecule) and there are many different types of TCRs, including both ɑß and уδ TCR+ cells, that can recognize different lipid antigens presented by CD1d. These are often classed as diverse NKT cells or Type-2 NKT cells. Moreover, humans also have CD1a, CD1b and CD1c restricted T cells, each with distinct patterns of lipid antigen reactivity. Furthermore, another population of innate-like T cells, known as mucosal associated invariant T (MAIT) cells, carries yet another invariant TCR-ɑ chain (Vɑ7.2-Jɑ33) that facilitates recognition of microbial-derived vitamin-B metabolites presented by MR1 (also an MHC class-I-like molecule). Collectively, these different populations can comprise up to 30% of T cells and in some tissues such as liver, they can represent up to 50% of these cells. Many studies have demonstrated that innate like T cells play a unique role in the immune system, they have been implicated in infection, cancer, autoimmunity and allergy. If we are to properly understand the immune system, it is vital that we understand the different types of innate-like T cells, the different classes of TCRs they use, and the antigens they target. Recent progress in our understanding of these cells, the antigens they recognize, will be presented.