Previous phylogenetic studies of the tribe Synergini were focused on Palaearctic material, in which the genus Synergus was recovered as monophyletic, despite evidence of non-monophyly when global sampling is considered. A global molecular phylogeny of Synergini, including sequenced material from Nearctic and Neotropical realms, is presented herein for the first time. We assembled DNA data for 120 specimens: 104 representing all genera belonging to Synergini, except for the rare monospecific genus Agastoroxenia (ingroup), and 16 belonging to five other tribes of Cynipidae (outgroup). We obtained sequences for four genes: cytochrome c oxidase subunit I (COI), cytochrome b (Cytb), 28S region D2 (28S D2) and 28S region D3 (28S D3). The evaluated analyses support the non-monophyly of both Saphonecrus and Synergus (with Nearctic and Neotropical Synergus resolved into three clades separated from the Palaearctic species), as well as the monophyly of the rest of the genera in Synergini. Furthermore, the results suggest that neither Saphonecrus s.s. nor Synergus s.s. are present in the New World. The future challenges to separate the clades of Saphonecrus and Synergus into new taxa are discussed. Lastly, Rhoophilus was shown to belong to a new tribe, Rhoophilini trib. nov., on the basis of molecular, morphological and biological data.