Abstract Background Glioma interventional studies should collect data aligned with patient priorities, enabling treatment benefit assessment and informed decision-making. This requires effective data synthesis and meta-analyses, underpinned by consistent trial outcome measurement, analysis, and reporting. Development of a core outcome set (COS) may contribute to a solution. Methods A 5-stage process was used to develop a COS for glioma trials from the UK perspective. Outcome lists were generated in stages 1: a trial registry review and systematic review of qualitative studies and 2: interviews with glioma patients and caregivers. In stage 3, the outcome lists were de-duplicated with accessible terminology, in stage 4 outcomes were rated via a 2-round Delphi process, and stage 5 comprised a consensus meeting to finalize the COS. Patient-reportable COS outcomes were identified. Results In Delphi round 1, 96 participants rated 35 outcomes identified in stages 1 and 2, to which a further 10 were added. Participants (77/96) rated the resulting 45 outcomes in round 2. Of these, 22 outcomes met a priori threshold for inclusion in the COS. After further review, a COS consisting of 19 outcomes grouped into 7 outcome domains (survival, adverse events, activities of daily living, health-related quality of life, seizure activity, cognitive function, and physical function) was finalized by 13 participants at the consensus meeting. Conclusions A COS for glioma trials was developed, comprising 7 outcome domains. Additional research will identify appropriate measurement tools and further validate this COS.