Macadamia is an evergreen native rainforest tree originating from the Australian east coast. The survival of these trees in their natural habitat was threatened when the land was cleared for agricultural use in the mid-1800s. However, commercial cultivation of the macadamia nut through the establishment of plantations in the 1870s ensured its survival, and today macadamia is Australia’s only indigenous, commercially grown food crop. By the 1890s, the macadamia nut had been introduced to some regions of the United States, such as Hawaii, where hybridization and cloning developed different varieties, such as Cates, Beaumont’s, and James, turning the nut into a valuable commercial crop. In addition to Australia and Hawaii, the tree is now also cultivated as a food crop in California, Florida, New Zealand, southern Africa, and parts of South and Central America. In Australia, there are at least five species of macadamia trees, but only two produce edible nuts and are grown as a food crop. They are Macadamia integrifolia (smooth shelled), which contains 80% oil and 4% sugar, and Macadamia tetraphylla (rough shelled) with an oil content which ranges from 65% to 75% and a sugar content of 6% to 8%. M. integrifolia is the species most commonly grown for its crops of nuts. This chapter focuses on the nutrient composition and health benefits of consuming macadamia nuts as part of a healthy diet.