G-protein coupled receptor 151 is a protein that in humans is encoded by the GPR151 gene. It is weakly activated by galanin, but its endogenous ligand remains unknown. Studies have suggested GPR151 may play a role in several clinically significant processes such as inflammation, pain perception and reward-seeking behavior as well as hepatic glucose production, but further research into its function has been limited so far by a lack of selective agonists and antagonists for this receptor, with most research to date using knockout mice.