OBJECTIVE: Glioblastoma (GBM) is an aggressive brain tumor characterized by significant heterogeneity. This study investigates the role of glycosylation-related genes in GBM subtyping, prognosis, and response to therapy. METHODS: We analyzed mRNA expression data and clinical information from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Glycosylation-related genes were selected for differential expression analysis, sample clustering, and survival analysis. Immune cell infiltration and drug sensitivity were evaluated using CIBERSORT and oncoPredict, respectively. A prognostic model was constructed with Lasso regression. RESULTS: GBM samples were stratified into two glycosylation-related subtypes, showing distinct survival outcomes, with higher glycosylation expression correlating with poorer prognosis. Immune microenvironment analysis revealed differences in T-cell infiltration and immune checkpoint expression between subtypes, indicating variable immunotherapy responses. The prognostic model based on glycosylation genes demonstrated significant predictive value for patient survival. CONCLUSION: Glycosylation-related gene expression contributes to GBM heterogeneity and is a valuable biomarker for prognosis and treatment stratification. This study provides insights into personalized treatment approaches for GBM based on glycosylation-related molecular subtypes.