SummaryT cells are known to migrate to B‐cell‐enriched follicles and germinal centers within secondary lymphoid organs to provide help to B cells. Cognate T:B interactions that take place at the T:B border and subsequently within germinal centers are essential for B‐cell priming, differentiation into germinal center B cells, and selection of mutated cells into memory B cells or memory plasma cells. In recent years, different stages of maturation within B‐cell helper T cells, collectively known as B‐follicular helper T (Tfh) cells, as well as heterogeneity amid germinal center T cells are becoming clear. Indeed, germinal centers support not only bona fide Tfh cells but also CD4+ and CD8+ follicular regulatory T (Tfr) cells that act to suppress germinal center responses and B‐cell helper natural killer T cells. There is a growing need for more precise phenotypic and functional distinction of these specialized T‐cell subsets. In this review, we summarize current knowledge on the ontogeny, molecular identity, and functional relevance of the various subsets of germinal center T cells.