This study presents investigation of sessile oak cynipid gall wasps fauna of Mt Fruška Gora. Gall wasps are insects, from the family Cynipidae, that induces galls mainly on oaks. Complex of sessile oak cynipid gall wasps were investigated during 4-year period (2016 – 2019). The survey was carried out on five sites: Kraljeve stolice, Spomenik, Brankovac, Ležimir and Rohalj baze. At total, number of seventeen cynipid gall wasps species were identified: Andricus aries (Girauld, 1859), Andricus caliciformis (Giraud, 1859), Andricus coriarius (Hartig, 1843), Andricus curvator (Hartig, 1840), Andricus dentimitratus (Rejto, 1887), Andricus glutinosus (Giraud, 1859), Andricus kollari (Hartig, 1843), Andricus lignicolus (Hartig,1840), Andricus lucidus (Hartig, 1843), Andricus solitarius (Fonscolombe, 1832), Cynips quercusfolii (Linnaeus, 1758), Cynips quercus(Fourcroy, 1785), Biorhiza pallida (Oliver, 1791), Neuroterus albipes (Schenck, 1863), Neuroterus anthracinus (Curtis, 1838), Neuroterus numismalis (Fourcroy, 1785) and Neuroterus quercusbaccarum (Linnaeus, 1758). Gall wasp A. dentimitratus is first record for Serbia. The most frequent species were A. lignicolus and A. glutinosus, which were found on all five observed sites.