Cancer cells preferentially use aerobic glycolysis to support growth, a metabolic alteration commonly referred to as the ‘Warburg effect.’ Here, we show that the tumor necrosis factor receptor-associated protein 1 (TRAP1) is crucial for the Warburg effect in human glioblastoma multiforme (GBM). In contrast to normal brain, GBMs show increased TRAP1 expression. We used both GBM cell lines and neurospheres derived from human GBM specimens to examine the effects of Knockdown of TRAP1 on GBM cell lines and glioma stem cells. We also used a neurosphere recovery assay that measured neurosphere formation at three time points to assess the capacity of the culture to repopulate after knockdown of TRAP1. Our results showed that knockdown of TRAP1 strongly decreased GBM cell proliferation and migration, inhibited neurosphere recovery, secondary neurosphere formation, and enhanced the therapeutic effect of temozolomide in neurosphere cultures. In GBM, knockdown of TRAP1 appeared to inhibit tumor growth and migration through its regulatory effects on metabolic reprogramming.