Axon regeneration after nerve injury requires generation of injury signals, elaboration of a growth cone, and target-directed growth. Little is known about the role of mitochondria during axon regeneration. Here we use in vivo single-neuron analysis to investigate the relationship between nerve injury, mitochondrial localization, and axon regeneration. Mitochondria accumulate in injured axons, and axons that fail to increase mitochondria have poor regeneration. Experimental alterations to mitochondrial distribution or mitochondrial respiratory chain function result in corresponding changes to regeneration outcomes. Axonal mitochondria are specifically required for growth cone migration, identifying a key energy challenge for injured neurons. Finally, mitochondrial localization to the axon after injury is regulated in part by dual-leucine zipper kinase-1 (DLK-1), a conserved regulator of axon regeneration. These data identify regulation of axonal mitochondria as a new cell biological mechanism that helps determine the regenerative response of injured neurons.