<p>O-GlcNAcylation is a dynamic, reversible post-translational modification that attaches N-acetylglucosamine (GlcNAc) to the serine or threonine residues of intracellular proteins. Catalysed by O-GlcNAc transferase and removed by O-GlcNAcase, this modification acts as a key nutrient and stress sensor. Although cell adhesion is fundamental to tissue architecture and mechanotransduction, emerging evidence has shown that O-GlcNAcylation profoundly orchestrates these processes. By modulating the composition and signalling of adhesion complexes, O-GlcNAcylation regulates both cell–cell and cell–matrix interactions. Through crosstalk with phosphorylation, this modification drives cellular adhesion plasticity, with broad implications for development, immunity, and diseases, such as cancer and neurodegeneration. Recent advances revealed that O-GlcNAcylation fine-tunes key regulators, including Focal Adhesion Kinase (FAK), Zyxin, and integrins, to control focal adhesion turnover. These mechanistic insights pave the way for novel therapeutic strategies targeting glycosylation-dependent adhesion signalling.</p>