Insects of the infraorder Cicadomorpha cause serious economic impact on agriculture because of pathogens' transmission. The vector-borne bacterium Xylella fastidiosa, which is associated with olive quick decline syndrome, is exclusively transmitted by insects of this infraorder and more specific by sharpshooters and spittlebugs. Efficient control practices of the insect vectors are necessary for the control of the disease in cases of outbreaks. Therefore, the knowledge of the vectors' species as well as the robust understanding of their biology and ecology is of crucial importance. In the present study, extensive sampling was conducted in 28 olive orchards of Greece during the years 2017 and 2018 aiming to investigate which species of this infraorder are present, with special interest to those which are considered as vectors of the bacterium. During the surveys, 4,350 Cicadomorpha insects were collected. Forty-two, five and one species of the families Cicadellidae, Aphrophoridae and Cercopidae, respectively, were identified. The results of the surveys revealed that the main potential vectors of X. fastidiosa in Greek olive orchards are the spittlebugs Philaenus spumarius and Neophilaenus campestris. Those species have wide distribution in Greece and are present for a long period during the year, and they inhabit both the ground vegetation and the olive trees' canopy. A representative portion of the captured spittlebugs was analysed with molecular methods, and the analysis confirmed the absence of X. fastidiosa in the tested individuals.