Germinal centre (GC) responses, during which CD4+CXCR5hiPD-1hi T follicular helper (TFH) cells provide help to B cells, are crucial for the development of affinity-matured antibodies and memory B cells, but they require careful regulation to limit autoantibody generation. Regulatory cells in and around GCs include a subset of CD4+FOXP3+CD25hi T regulatory (Treg) cells termed T follicular regulatory (TFR) cells. Intriguingly, TFR cells can suppress and/or enhance humoral responses.