GPR34 is a rhodopsin-like class G protein-coupled receptor (GPCR) that is involved in the development and progression of several diseases. Despite its importance, effective targeting strategies are lacking. We herein report a series of (S)-3-(4-(benzyloxy)phenyl)-2-(2-phenoxyacetamido)propanoic acid derivatives as a new class of GPR34 antagonists. Structure-activity relationship (SAR) studies led to the identification of the most potent compound, 5e, which displayed an IC₅₀ value of 0.680 μM in the GloSensor cAMP assay and 0.059 μM in the Tango assay. 5e demonstrated low cytotoxicity and high selectivity in vitro, and it was able to dose-dependently inhibit Lysophosphatidylserine-induced ERK1/2 phosphorylation in CHO cells expressing GPR34. Furthermore, 5e displayed excellent efficacy in a mouse model of neuropathic pain without any apparent signs of toxicity. Collectively, this study has identified a promising compound, which shows great potential in the development of potent antagonists with a new chemical scaffold targeting GPR34.