Abscisic acid (ABA) regulates fruit ripening, yet little is known about the exact roles of ABA receptors in fruit. In this study, we revealed the role of SlPYL9, a tomato PYR (pyrabactin resistance) / PYL (pyrobactin resistance-like) / RCAR (regulatory component of ABA receptors) ABA receptor, as a positive regulator of ABA signaling and fruit ripening. SlPYL9 inhibited protein phosphatase-type 2C (PP2C2/6) in ABA dose-dependent way, and it interacts physically with SlPP2C 2 / 3 / 4 / 5 in an ABA-dependent manner. Expression of SlPYL9 was observed in the seeds, flowers and fruit. Overexpression and suppression of SlPYL9 induced a variety of phenotypes via altered expression of ABA signaling genes (SlPP2C1/2/9, SlSnRK2.8, SlABF2), thereby affecting expression of ripening-related genes involved in ethylene release and cell wall modification. SlPYL9-OE / RNAi plants showed a typical ABA hyper- / hypo-sensitive phenotype in terms of seed germination, primary root growth and the response to drought. Fruit ripening was significantly accelerated in SlPYL9-OE by 5-7 days as a result of increased endogenous ABA accumulation and advanced release of ethylene compared with the wild-type (WT). Meanwhile, in the SlPYL9-RNAi lines, fruit ripening was delayed, mesocarp thickness was enhanced, and the petals did not abscise as timely as the WT, resulting in conical / oblong and gourd-shaped fruit. These results suggest that SlPYL9 is involved in ABA signaling, thereby playing a role in the regulation of flower abscission and fruit ripening in tomato.