Abstract: This investigation was carried out on Roi-Et soil series (Oxic Paleustults) at Chaiyaphum Province, Northeast Thailand during October 2004 to June 2005. The study aimed to justify the effect of different rates of Gibberellin (GA3) on yield and fruit quality of Kaew mango cv. Srisaket 007 (Mangifera indica L.). The study was laid in a Randomized Complete Block Design (RCBD) with four replications. Five rates of GA3 were used, i.e., 0 (T1, control), 1,953.25 (T2), 3,906.50 (T3), 5,859.75 (T4) and 7,813.00 ppm ha-1 (T5) with the actual rates being used of 0, 50, 100, 150 and 200 ppm for T1 up to T5, respectively, i.e., each rate was used for four replications of four mango trees of each treatment. The results showed that the application of GA3 at a rate of 1,953.25 ppm ha-1 or 12.50 ppm plant-1 appliedto Kaew mango cv. Srisaket 007 gave the highest mango fresh fruit yield of 32,066.83 kg ha-1. All rates of GA3 being used had no significant effect on harvesting age, width, flesh firmness and total soluble solids of mango fruits but highly increased % of panicles with survived fruits, fruit yield ha-1, fruit flesh content, fruit thickness, individual fruit weight and titratable acidity of flesh of fruits and also significantly increased in length of the mango fruits. GA3 at a rate of 1,953.25 ppm ha-1 or 12.50 ppm plant-1 is needed for high fruit production whenever mango trees started to produce flowers.