Gliomas are the most common malignant brain neoplasms with high recurrence and lethality rates. Recently, studies have reported that cyclin-dependent kinase 5 (CDK5) is involved in tumorigenesis. Herein, we applied bioinformatics analysis to determine the clinical value of CDK5 in patients with glioma and examined the effects of CDK5 on glioblastoma cell proliferation, apoptosis, and cell cycle . Gene expression profiles containing clinical data of low-grade glioma (LGG) and glioblastoma cohorts were obtained from The Cancer Genome Atlas database and analyzed to determine the association between CDK5 expression and glioma clinicopathological characteristics. Kaplan-Meier survival analysis was performed for prognosis analysis. Gene set enrichment analysis (GSEA) was used to identify the biological pathways involved in differential CDK5 expression. experiments were performed to explore the effects of CDK5 on glioma cell functions. CDK5 expression was substantially higher in glioblastoma than in LGG. GSEA showed that some metabolism-related pathways were associated with the high CDK5 expression phenotype. experiments showed that CDK5 knockdown impaired cell proliferation and colony formation ability, and induced apoptosis and cell cycle arrest. CDK5 may act as a potential biomarker of glioma progression and a valid target for glioma therapy.