Siglec proteins, short for sialic acid-binding immunoglobulin-type lectins, are a family of cell surface receptors predominantly expressed on immune cells. These proteins specifically recognize sialic acids, a family of sugar molecules that adorn the surfaces of cells, marking them as 'self' and influencing immune cell interactions. Siglecs play a pivotal role in the immune system, helping to modulate immune responses, maintain tolerance, and prevent autoimmunity by distinguishing between self and non-self. Each Siglec has a distinct pattern of sialic acid recognition, contributing to a wide range of biological processes, including cell-cell communication, inflammation, and the shaping of the immune landscape. Dysregulation of Siglec signaling pathways is implicated in various diseases, such as cancer, neurodegeneration, and inflammatory conditions, making them significant targets for therapeutic intervention. With their unique binding capabilities and regulatory functions, Siglec proteins remain a focus of intense research, promising new insights into immune regulation and offering avenues for innovative drug development.