<p>Non-small cell lung cancer (NSCLC), the most common type of lung cancer, is a leading cause of cancer death. G protein-coupled receptor 54 (GPR54) plays a role in cancer development by interacting with its endogenous ligand kisspeptin encoded by the <i>KISS1</i> gene. However, the role of GPR54 in NSCLC development is not yet fully understood. Here, we demonstrate that GPR54 regulates NSCLC development via dopa decarboxylase (DDC). A mutant <i>Kras</i>-driven mouse lung cancer model revealed that adenoviral <i>CMV-Cre</i>-mediated <i>Gpr54</i> deletion attenuated NSCLC development. Both <i>Gpr54</i> deletion in mouse NSCLC tissues and <i>GPR54</i> knockdown in human NSCLC cell lines caused apoptotic cell death. In addition, GPR54 regulation of NSCLC cell proliferation involves both the Gα_q/11/AKT and β-arrestin/ERK signaling pathways. RNA sequencing revealed that <i>Gpr54</i> deletion altered a gene set related to glycolysis and genotype-dependently regulated <i>Ddc</i> gene expression. Moreover, the regulation of glycolysis and <i>DDC</i> expression by GPR54 was dependent on the Gα_q/11/PI3K/AKT/mTOR signaling pathway. Phosphoprotein arrays further revealed that DDC regulated NF-κB phosphorylation in NSCLC cells. Consistently, DDC regulated both NSCLC cell proliferation in vitro and tumor growth in vivo. Overall, our findings suggest that GPR54 could be a diagnostic marker for NSCLC and that therapeutics targeting GPR54 signaling may be useful for treating NSCLC.</p>