Postharvest application of 200 ppm gibberellic acid (GA3) to "Kheaw Sawoey" mango fruit immediately after harvest significantly delayed ripening for two days so that it can still be marketed as green mango. Other changes in peel color, pulp color, firmness, soluble solids, titratable acidity, conversion of starch to sugars, and solubilization of pectic substances were also delayed. Among the fruit attributes studied, the delay in peel color development was the most prominent GA3 effect both in immature and mature fruits. However, other ripening changes in mature fruits were evidently delayed. This can be attributed to the effect of GA3 on sensitivity of the tissue to ethylene. GA3 partially affected respiration rate but not ethylene biosynthesis. Results from this study showed that GA3 delayed ripening of "Kheaw Sawoey" mango through inhibition of some ethylene-mediated ripening changes.