Background: Glucagon-like peptide-1 receptor (GLP-1R) agonists are increasingly prescribed for type 2 diabetes mellitus and obesity treatment. Preclinical evidence in glioblastoma cell lines suggests antitumour activity through ferroptosis induction; however, the transcriptomic and prognostic contexts of GLP1R expression in human IDH-wildtype glioblastoma are poorly characterised. Methods: We analysed GLP1R mRNA expression and its survival, immune, and ferroptosis correlates in IDH-wildtype primary glioblastoma across three cohorts: TCGA-GBM (discovery, n=245), CGGA_mRNAseq_693 (n=105), and CGGA_mRNAseq_325 (n=74) as pre-specified validation. Continuous-variable multivariable Cox regression was adjusted for age, KPS, MGMT methylation, and treatment. Pre-ranked GSEA, ssGSEA immune deconvolution, and ferroptosis-axis correlations were pre-specified, and replication was scored against a 13-criterion scorecard. Reporting followed the REMARK guidelines. Findings: Across 424 patients, GLP1R expression showed a protective hazard direction in all three cohorts (adjusted HR 0·81, 0·393, and 0·094 in TCGA, CGGA_693, and CGGA_325, respectively), without reaching statistical significance in any individual dataset. GLP1R-high tumours showed reproducible depletion of TNFα/NF-κB signalling, interferon-γ response, glycolysis, and oxidative phosphorylation across all three cohorts, an immune-cold microenvironment (eight Bindea signatures directionally negative in CGGA_693), and a discovery-cohort association with reduced NRF2/redox transcriptional tone (NFE2L2, HMOX1) that did not replicate in external validation. Interpretation: GLP1R expression delineates a transcriptomically coherent, immune-cold subgroup of IDH-wildtype glioblastoma. These findings provide a clinical context for the experimental GLP-1R–ferroptosis axis, although the axis itself did not replicate across cohorts, and a biological rationale for biomarker-stratified evaluation of GLP-1R agonists, ferroptosis inducers, and immune-priming combinations in this uniformly lethal disease.