Mouse CXCL12 (C-X-C motif chemokine ligand 12), also known as SDF-1 (stromal cell–derived factor-1), is a homeostatic chemokine belonging to the CXC chemokine family that plays a central role in cell migration, immune cell trafficking, and tissue development. In mice (Mus musculus), CXCL12 is produced by stromal cells, endothelial cells, epithelial cells, fibroblasts, and bone marrow niche cells, where it regulates the migration and positioning of hematopoietic stem cells, lymphocytes, and other progenitor cells. CXCL12 primarily signals through the receptors CXCR4 and ACKR3 (CXCR7), guiding immune cells and stem cells to specific tissues and supporting hematopoiesis, immune surveillance, and tissue repair. The CXCL12–CXCR4 signaling axis is highly conserved and essential for embryonic development, vascular formation, and maintenance of bone marrow stem cell niches. Mouse models have been instrumental in understanding this pathway; for example, CXCL12 or CXCR4 knockout mice exhibit embryonic lethality due to defects in hematopoiesis, cardiovascular development, and neuronal migration, demonstrating the critical role of this chemokine system. Consequently, mouse CXCL12 is widely studied in stem cell biology, cancer metastasis, immune cell trafficking, and regenerative medicine, making it a key component of experimental models investigating chemokine signaling and tissue development.