Abstract: Fluid flow in the brain is an emerging area of research with implications in Alzheimer’s, aging, brain homeostasis, development, and cancer. In glioblastoma, fluid flow is increased at the tumor border, where cells invade and interact with surrounding parenchyma. Increased interstitial fluid flow, or the flow within the extracellular spaces, leads to invasion of tumor cells through multiple mechanisms. This invasion can be seen in vivo in regions of heightened flows when using MRI imaging methodology. The role of interstitial fluid flow in glioma outcomes in a pre-clinical and clinical setting will be discussed.