Modulation of sensory function can help animals adjust to a changing external and internal environment. Even so, mechanisms for modulating taste sensitivity are poorly understood. Using immunohistochemical, biochemical, and behavioral approaches, we found that the peptide hormone glucagon‐like peptide‐1 (GLP‐1) and its receptor (GLP‐1R) are expressed in mammalian taste buds. Furthermore, we found that GLP‐1 signaling plays an important role in the modulation of taste sensitivity: GLP‐1R knockout mice exhibit a dramatic reduction in sweet taste sensitivity as well as an enhanced sensitivity to umami‐tasting stimuli. Together, these findings suggest a novel paracrine mechanism for the hormonal modulation of taste function in mammals.