Glycoproteins are naturally produced by protein glycosylation and are involved in a wide range of cellular functions. This Review aims to summarize the preparation of well-defined synthetic glycoproteins by using chemical routes as well as to highlight the preparation of ideal polymeric analogues of natural glycoproteins: glycopolypeptides. These macromolecules are simplified models of glycoproteins and are designed with the purpose of both mimicking the properties of natural glycoproteins as well as bringing innovative polymeric structures for materials science applications.