This study investigated the effect of different pH levels on in vitro pollen germination and pollen tube growth in Pistacia palaestina, Pistacia terebinthus, Pistacia atlantica, Pistacia khinjuk, and Pistacia vera cv Kaska. Pollen susceptibility of Pistacia species to acidity or alkalinity of germination medium (pH 2.0, 3.0, 4.0, 5.0, 6.0, 6.7 (distilled water), 7.0, 8.0 and 9.0) were tested. It was found that pollen germination and pollen tube growth for all species were greatly reduced when grown in the pH 3.0 medium. None of the pollen of the Pistacia species could germinate at pH 2.0. With growth mediums between pH 3.0 and 9.0, the amount and pattern of response in pollen germinability and tube growth varied considerably between species. According to mean pollen germination, the highest value was obtained at pH 6.0 (93.29%), while pH 3.0 had the lowest value, with 12.08%. The pollen tube growth of the species ranged from 87.6 mu m (pH 3.0) to 1054.6 mu m (pH 9.0). The pH of the germination medium also affected differentiation in pollen germination and pollen tube growth between the genotypes.