In Wilson disease (WD), toxic copper overload occurs due to an impaired copper excretion from the liver. Mitochondria, the power plants of all higher eukaryotic cells, are fundamentally dependent on copper to fulfill their bioenergetic tasks. This is ensured by the regulated routing of copper to these organelles. However, in WD patients and animal models, mitochondria are directly and progressively damaged by copper overload. This leads to increasing, characteristic mitochondrial structure alterations and to severe bioenergetic impairments. Finally, mitochondrial destruction is paralleled by liver failure and death. Especially, interventions with copper-chelators that cause efficient reduction of the mitochondrial copper load result in the restoration of their structure and function, avoid acute liver failure in WD and are thus promising options for future WD therapies.