Glycerolysis is an effective method for lowering free fatty acid (FFA) levels in vegetable oils, including red palm oil (RPO), thereby improving overall oil quality. This study examined the effects of key process variables—molar ratio of FFA to glycerol, reaction temperature, stirring speed, and catalyst loading—on the glycerolysis of RPO using potassium hydroxide (KOH) as a catalyst. Best conditions were achieved at an FFA-to-glycerol molar ratio of 1:4, a reaction temperature of 80 °C, a stirring speed of 300 rpm, and a catalyst loading of 0.7% (w/w oil), resulting in 96% FFA conversion within 90 minutes. Under these conditions, the FFA content was reduced from 13.69% to 0.55%. The glycerolysis process effectively lowers the FFA, peroxide, and saponification values of the oil, while having no significant impact on its density, viscosity, or fatty acid composition.