The vast majority of the human genome is transcribed into noncoding RNAs. Among these, microRNAs (miRNA) and long noncoding RNAs (lncRNA) are frequently deregulated in cancer, where they regulate a wide variety of functions. Glioblastoma (GBM) is the most common and the most deadly primary human brain tumor. This chapter reviews the deregulation, functions, mechanisms of action, and clinical applications of miRNAs and lncRNAs in GBM. miRNAs are short noncoding RNAs that broadly and profoundly regulate gene expression. Numerous miRNAs are deregulated in GBM, where their expression levels can serve as diagnostic and prognostic biomarkers. miRNAs can act as oncogenes or tumor suppressors in GBM by regulating the expression of numerous tumor-suppressive or oncogenic proteins. miRNAs regulate all GBM malignancy parameters including tumor cell proliferation, cell survival, invasion, angiogenesis, cancer stem cells, immune escape, and therapy resistance. miRNAs are also secreted in body fluids, where they can be used as biomarkers. Because of their deep involvement in GBM malignancy, efforts are under way to also exploit miRNAs as therapeutic agents or targets. lncRNAs are a diverse group of noncoding RNAs that are >200 nucleotides long. Several lncRNAs are deregulated in GBM, where their expressions can associate with clinical parameters. lncRNAs regulate GBM functions including tumor cell proliferation, survival, invasion, cancer stem cell differentiation, and therapy resistance. lncRNAs exert their actions via transcriptional, post-transcriptional, and epigenetic mechanisms that are only partly understood. Studying noncoding RNAs is important for the understanding, management, and development of future therapies for GBM.