Suppressive activities involving T‐B and T‐T cell interactions are important to maintain immune system homeostasis. Negative control of IgG2ab + B cells by anti‐IgG2ab T cells derived from Igha mice has been well documented. Nevertheless the real contribution of anti‐IgG2ab T cells, endogenously matured in Ighb mice, in controlling IgG2ab + B cell function has never been investigated. We previously generated anti‐IgG2ab TCR‐transgenic mice and showed that transgenic T cells were not deleted in the thymus and that they were responsible for a complete and chronic IgG2ab suppression. Here we show that T cells expressing high density of anti‐IgG2ab TCR were positively selected in the thymus with a higher efficiency in animals expressing IgG2ab, reached peripheral lymphoid organs and negatively controlled IgG2ab serum levels. Moreover, anti‐IgG2ab T cells transgenic for the single TCR β chain, thus undergoing normal α rearrangements and normal processes of selection, also reached the periphery and suppressed IgG2ab. Interestingly, concentration of IgG2ab in serum inversely correlated with the peripheral frequency of Ig‐specific T cells. Finally, T cells able to suppress IgG2ab were obtained from Ighb non‐transgenic mice, indicating that anti‐γ2ab T cells are naturally present in the periphery of Ighb animals. We propose that IgG2ab‐specific T cells contribute to determine IgG2ab serum levels in Ighb mice.