1) Thevetia Nerifolia seed oil was extracted and characterized, with an iodine value of 92.46 indicating it contains predominantly polyunsaturated fatty acids. 2) The oil was then epoxidized, lowering its iodine value to 19.65 due to reduced unsaturation. 3) Soybean adhesive was modified by adding 20% epoxidized Thevetia Nerifolia oil, improving its water resistance over three soak cycles compared to the unmodified adhesive.