Gliomas represent a group of the most common malignant brain tumors with variable behavior and prognosis. Based on the histopathological classification, these tumors are divided into prognostically more favorable low-grade gliomas and high-grade gliomas, which are generally more aggressive. However, even within these groups, the prognosis varies considerably between patients, and histopathological examinations cannot predict individual risk. Therefore, it is crucial to find new molecular biomarkers able to predict clinical response in glioma patients and, thus, help to more individualize their treatment. The tumor microenvironment plays an important role in disease manifestation, and its stimulation is essential for gliomagenesis. Exosomal microRNAs (miRNAs) could represent one form of intercellular communication over both short and longer distances. These highly stable small non-coding RNAs are post-transcriptional repressors of gene expression involved in regulating almost all cellular and biological processes. Their important role is further reinforced by the fact that aberrant miRNA levels are associated with the development of many diseases, including gliomas. Moreover, exosomes exhibit their own unique donor cell surface structures that increase their affinity for stromal cells present in the microenvironment. Thus, exosomal miRNAs circulating in cerebrospinal fluid could represent a promising diagnostic tool to predict glioma behavior and patient prognosis. At the same time, a deeper understanding of the mechanism of communication within the tumor microenvironment could lead to a new therapeutic strategy not only in gliomas but also in other cancers.