Biodiesel production provides a diversified and renewable energy source offering lower greenhouse gas emissions than traditional diesel. It also offers economic benefits by reducing dependence on imported fossil fuels. Castor oil transesterification is an essential process in the creation of biodiesel. In this experimental study, castor oil transesterified using methanol, and potassium hydroxide was the catalyst. The effects of various reaction parameters, including temperature, the molar ratio of methanol to oil, and catalyst concentration, on the biodiesel yield were studied and optimized by the conventional method followed by the statistically based Box-Behnken design method. The maximum yield was reached at a temperature of 65°C, a molar ratio of 12:1 methanol to oil, and a catalyst concentration of 1.5% by weight. The yield of biodiesel under these conditions was 93%. The optimized results of experiments showed increases in yield to 93.36% at 65°C temperature, 14.12:1 a molar ratio methanol to oil, and a 1.12% by weight catalyst concentration; hence, the optimal temperature was the highest achieved value. The fatty acid methyl ester composition analysis revealed that the major constituents of the biodiesel were ricinoleic acid methyl ester, linoleic acid methyl ester, and oleic acid methyl ester. The findings of this research highlight the significance of selecting the appropriate reaction conditions to maximize biodiesel yield. Also, it was found that castor oil had the potential to be an essential feedstock for biodiesel production.