Purpose: To systematically review and examine current evidence for the carer-reported benefits of supportive care strategies for carers of adults with high-grade glioma (HGG). Methods: Four databases (CINAHL, EMBASE, PubMed, PsycINFO) were searched for articles published between January 2005 and April 2022 that assessed strategies for addressing the supportive care needs of carers of adults with HGG (WHO grade 3–4). Study selection and critical appraisal were conducted independently by three authors (DJ/MC, 2021; DJ/RJ 2022). Data extraction was conducted by one author (DJ) and checked by a second author (RJ). Results were synthesised narratively. Results: Twenty-one studies involving 1377 caregivers were included, targeting the carer directly (n = 10), the patient-carer dyad (n = 3), or focused on people with HGG + / − their carers (n = 8). A paucity of high-quality evidence exists for effective and comprehensive support directly addressing outcomes for carers of adults with HGG. Strategies that demonstrated some benefits included those that built carer knowledge or provided emotional support, delivered by health professionals or through peer support. Supportive and early palliative care programmes have potential to reduce unmet carer needs while providing ongoing carer support. Conclusion: Strategies incorporating an educational component, emotional support, and a regular needs assessment with corresponding tailored support are most valued by carers. Future practice development research should adopt a value-based approach and exceed evaluation of efficacy outcomes to incorporate evaluation of the experience of patients, carers, and staff, as well as costs.