Methanolysis of sunflower oil was investigated in the presence of barium hydroxide as a catalyst. It was observed that the methanolysis reaction was both heterogeneously and homogeneously catalyzed. The heterogeneously catalyzed reaction is faster than the homogeneously catalyzed one and determines the overall reaction rate. Under optimum reaction conditions, a very high fatty acid methyl ester content was obtained within a few minutes. The barium hydroxide-catalyzed methanolysis is faster than the methanolysis catalyzed by calcium oxide and calcium hydroxide and comparable to the potassium hydroxide-catalyzed methanolysis.