Mouse Stem Cell Factor (SCF) (also known as KIT ligand, KITLG, mast cell growth factor, or steel factor) is a cytokine and growth factor that plays a fundamental role in hematopoiesis, stem cell maintenance, and immune cell development in mice (Mus musculus). SCF belongs to a group of hematopoietic growth factors that regulate the survival, proliferation, and differentiation of stem and progenitor cells. It functions by binding to the c-Kit receptor (CD117), a receptor tyrosine kinase expressed on hematopoietic stem cells, mast cells, melanocytes, and germ cells, activating intracellular signaling pathways including PI3K/AKT, MAPK, and JAK/STAT that regulate cell survival and proliferation. In mice, SCF is produced by bone marrow stromal cells, fibroblasts, endothelial cells, and epithelial cells, and exists in both membrane-bound and soluble forms, allowing both localized and systemic regulation of c-Kit–expressing cells. Mouse SCF is essential for maintenance of hematopoietic stem cells within the bone marrow niche, as well as for mast cell development, melanocyte function, and germ cell survival. Murine SCF and c-Kit signaling have been extensively studied using genetic mouse models such as the Steel (Sl) and White spotting (W) mutants, which exhibit defects in hematopoiesis, pigmentation, and fertility, making mice a foundational model for understanding SCF–c-Kit signaling. These studies have provided critical insights into stem cell biology, developmental processes, and oncogenic signaling pathways relevant to human disease.