Importance to the field: Glucose-dependent insulinotropic polypeptide (GIP) is an incretin hormone that potentiates nutrient-induced insulin release. To date, the physiological importance of GIP has received much less attention than its younger sister incretin hormone glucagon-like peptide-1. Thus, it is worthwhile to refocus on this important and somewhat neglected incretin hormone. Areas covered in this review: The potential role of GIP as a treatment option for type 2 diabetes is highlighted. Furthermore, the use of GIP as a new therapeutic option for obesity, osteoporosis and cognitive impairment is also considered. What the reader will gain: Long-acting GIP receptor agonists offer a potential new class of antidiabetic drugs. Furthermore, recent observations suggest an as yet untapped potential for GIP agonists in the treatment of osteoporosis and cognitive impairment. In addition, GIP is known to play a role in lipid metabolism and fat deposition. Accordingly, both genetic and chemical ablation of GIP signalling in mice with obesity-diabetes can protect against, or reverse, many of the obesity-associated metabolic disturbances. This review focuses on preclinical data generated to date. Take home message: GIP-based therapeutics have potential for the treatment of type 2 diabetes and obesity, with the possibility of further beneficial actions in osteoporosis and cognitive decline.