Metabolic dysregulation drives tumor initiation in a subset of glioblastomas harboring isocitrate dehydrogenase (IDH) mutations, but metabolic alterations in glioblastomas with wild-type IDH are poorly understood. MYC promotes metabolic reprogramming in cancer, but targeting MYC has proven notoriously challenging. Here, we link metabolic dysregulation in patient-derived brain tumor–initiating cells (BTIC) to a nexus between MYC and mevalonate signaling, which can be inhibited by statin or 6-fluoromevalonate treatment. BTICs preferentially express mevalonate pathway enzymes, which we find regulated by novel MYC-binding sites, validating an additional transcriptional activation role of MYC in cancer metabolism. Targeting mevalonate activity attenuated RAS-ERK–dependent BTIC growth and self-renewal. In turn, mevalonate created a positive feed-forward loop to activate MYC signaling via induction of miR-33b. Collectively, our results argue that MYC mediates its oncogenic effects in part by altering mevalonate metabolism in glioma cells, suggesting a therapeutic strategy in this setting. Cancer Res; 77(18); 4947–60. ©2017 AACR.