Mitochondria referred to as the "powerhouse of the cell," may play diverse roles beyond energy production. Recent studies reported certain mitochondrial genetic variants are associated with particular climate zones, suggesting a mitochondrial contribution to the capacity of populations to adapt to climate change. I tested this hypothesis, leveraging strains of fruit flies that differed in their mitochondrial genotype, to investigate whether the mitochondria carried by a fly determined its capacity to tolerate thermal stress. My results confirmed a mitochondrial contribution to performance under thermal stress, suggesting that mitochondrial variation may be a facilitator of evolutionary change to climate stress.