Abstract Vδ2 + T cells form the predominant human γδ T-cell population in peripheral blood and mediate T-cell receptor (TCR)-dependent anti-microbial and anti-tumour immunity. Here we show that the Vδ2 + compartment comprises both innate-like and adaptive subsets. Vγ9 + Vδ2 + T cells display semi-invariant TCR repertoires, featuring public Vγ9 TCR sequences equivalent in cord and adult blood. By contrast, we also identify a separate, Vγ9 − Vδ2 + T-cell subset that typically has a CD27 hi CCR7 + CD28 + IL-7Rα + naive-like phenotype and a diverse TCR repertoire, however in response to viral infection, undergoes clonal expansion and differentiation to a CD27 lo CD45RA + CX 3 CR1 + granzymeA/B + effector phenotype. Consistent with a function in solid tissue immunosurveillance, we detect human intrahepatic Vγ9 − Vδ2 + T cells featuring dominant clonal expansions and an effector phenotype. These findings redefine human γδ T-cell subsets by delineating the Vδ2 + T-cell compartment into innate-like (Vγ9 + ) and adaptive (Vγ9 − ) subsets, which have distinct functions in microbial immunosurveillance.