Nuts and dried fruit are essential foods in the Mediterranean diet. Their frequent consumption has been associated with the prevention and/or the management of such metabolic conditions as type 2 diabetes (T2D), metabolic syndrome and cardiovascular diseases. Several previous reviews of epidemiological studies and clinical trials have evaluated the associations of nuts and/or dried fruit with various metabolic disorders. However, no reviews have focused on the mechanisms underlying the role of nuts and/or dried fruit in insulin resistance and T2D. This review aims to report nut and dried-fruit nutritional interventions in animals and humans, and to focus on mechanisms that could play a significant role in the prevention and treatment of insulin resistance and T2D.