Glycolipids are lipids that are attached to a short carbohydrate chain (mono- or oligosaccharides). The role of glycolipids is to serve as markers for cell to cell communication and to provide energy. Glycolipids are collectively part of a larger family of substances known as glycoconjugates, which include glycoproteins, glycopeptides, proteoglycans, glycolipids, peptidoglycans and lipopolysaccharides.

Glycolips are normally found at the outer surface of cell membranes and are associated with phospholipids in the cell surface membrane.
According to the Oxford Glycobiology Institute, "Protein and lipid-linked oligosaccharides are a large component of the eukaryotic cell surface where they play important roles in cell-cell and cell-pathogen interactions and adhesion. Alterations in both the synthesis or catabolism of these oligosaccharides have serious and life threatening consequences, such as tumour metastasis, carbohydrate deficiency syndromes and lysosomal storage diseases.

"The experimental manipulation of oligosaccharide biosynthesis by the use of enzyme specific inhibitors has proved useful in understanding the functional roles of protein-linked oligosaccharides. When the early stages of oligosaccharide maturation are blocked with a-glucosidase inhibitors, such as N-butyl-deoxynojirimycin, many glycoproteins fail to undergo chaperone-mediated protein folding, leading to an altered conformation and loss of biological activity. This discovery has lead to the exploitation of processing inhibitors as anti-viral (HIV and Hepatitis B) therapeutics."

One of the glycolipids found in human red blood cells is involved in the antigens of the ABO blood type. Some glycoproteins are also involved with the antigens as well.