Walnut oil is oil extracted from walnuts, Juglans regia. The oil contains polyunsaturated fatty acids, monounsaturated fatty acids, and saturated fats. Walnut oil is composed largely of polyunsaturated fatty acids (72% of total fats), particularly alpha-linolenic acid (14%) and linoleic acid (58%), oleic acid (13%), and saturated fats (9%).