The recognition of various ingested dietary compounds enables the gastrointestinal tract to optimize nutrient digestion, absorption, and assimilation. Concurrently, the gastrointestinal tract also signals through hormonal and neuronal pathways to other tissues modulating various physiological events, such as short-term regulation of food intake and the initial defense responses against toxins/bacteria found in foods. While the physiological responses to dietary components are well characterized, the mechanisms of luminal signal identification and relay are not fully understood. G protein coupled receptors (GPCRs) often function as sensors for environmental cues, exemplified by photons, smells, and tastes, and chemical messengers released by cells such as hormones and neurotransmitters. Consequently, GPCRs can be activated by a wide range of molecules with distinct chemical properties (e.g. protons, metabolites, proteins). Therefore, GPCRs have the potential to sense luminal dietary compounds. The studies described in this dissertation investigated the effects of GPCRs expressed in the small intestinal mucosa that are directly or indirectly activated by luminal dietary nutrients. The study in Chapter 1 demonstrated that the activation of neuropeptide tyrosine receptors by peptide tyrosine tyrosine, which is released in response to dietary long chain fatty acids, induces cell migration linked to differentiation of enterocytes through processes mediated by a metalloproteinase, an adhesion molecule, and a RhoGTPase. The study in Chapter 2 showed that P2Y5 is a GPCR activated by lysophosphatidic acid (LPA; a bioactive phospholipid also found in foods) and farnesyl pyrophosphate (FPP; one of the intermediates in the steroid biosynthesis pathway) with unique G protein coupling preferences. The activation of P2Y5 could also regulate the activities of other receptor viz. the epidermal growth factor receptor and cholecystokinin receptor type A. The study in Chapter 3 examined the physiological relevance of GPR93 activated by its agonists (protein hydrolysate, LPA, and FPP) in the intestine. Activated GPR93 enhances wound healing, induction of hormone release, and neuronal activity. In conclusion, the activation of those three GPCRs in response to luminal dietary components modulates hormonal and neuronal signals affecting the gastrointestinal tract function and potentially the behavior of the organism.