Ovine (Ovis aries) and Caprine (Capra hircus) CCL2 (C-C motif chemokine ligand 2, also known as monocyte chemoattractant protein-1, MCP-1) are highly conserved chemokines that play a key role in recruitment and activation of monocytes, macrophages, and memory T cells during immune responses in small ruminants. Because the ovine and caprine proteins are identical in sequence, they exhibit the same functional properties and receptor interactions. CCL2 primarily signals through the CCR2 receptor, activating intracellular pathways that promote leukocyte migration, cytokine production, and coordination of innate and adaptive immune responses at sites of infection, inflammation, or tissue injury. In sheep and goats, CCL2 is particularly important in inflammatory and infectious diseases such as mastitis, pneumonia, gastrointestinal parasitic infections, and caseous lymphadenitis, where recruitment of monocytes and macrophages is essential for pathogen control and tissue repair. However, excessive or prolonged CCL2 expression may contribute to chronic inflammation and tissue damage. As a biomarker of monocyte/macrophage recruitment and inflammatory activation, ovine and caprine CCL2 are widely studied in investigations of host–pathogen interactions, vaccine responses, and immune regulation in small ruminant production systems. Characterization of CCL2 in these species supports veterinary research aimed at improving disease resistance, understanding inflammatory disease mechanisms, and enhancing the health and productivity of sheep and goats.