Background: People living with high-grade glioma (HGG) have diverse and complex needs. Screening aims to detect patients with some level of unmet need requiring triaging and further assessment. However, most existing measures of unmet need are not suitable for screening in this population due to their length. We aimed to explore the clinical utility of a brief screening tool (SCNS-ST9) in people with HGG in detecting unmet needs. Methods: Secondary analysis of data collected in a prospective cohort study of 116 people with HGG who completed the Supportive Care Needs Survey (SCNS-SF34) and a brain cancer-specific needs survey (BrTSCNS) during chemoradiation (T1) and 6 months later (T2). The SCNS-ST9 contains a subset of 9 items from the SCNS-SF34. Data analysis determined the number of individuals with unmet needs on the SCNS-SF34 and the BrTSCNS, not identified as having some level of need by the SCNS-ST9. Results: Overall, 3 individuals (T1: 2.6% [3/116]; T2: 4.8% [3/63]) at each time point reported other unmet needs on the SCNS-SF34 that were missed by the SCNS-ST9. Domain-specific screening items missed a higher proportion of individuals (3.2%–26%), particularly in the psychological and health systems domains. Only 1 individual with brain cancer-specific needs was missed by SCNS-ST9 overall. Conclusion: Findings demonstrate the sensitivity and clinical utility of a brief screening tool (SCNS-ST9) of unmet needs in people with HGG. Routine use of this screening tool, supported by clinical pathways, may improve access to support services, potentially reducing the burden of disease for these patients.