Ageing is accompanied by decreased overall fitness and performance. Studying brain ageing in humans is challenging due to limited or no access to healthy tissue, limited opportunities for interventions and complicated confounding factors. The generation of mouse ageing models with uniform genetic backgrounds significantly contributed to understanding (brain) ageing at the molecular level. Research has focused on evolutionarily conserved mechanisms or pathways that control ageing to facilitate data extrapolation to humans. Understanding how these pathways contribute to pathological ageing may help us understand human central nervous system (CNS) ageing and assist in the development of possible therapeutic targets. In this review, we focus on the functional consequences and pathological changes in the CNS of ageing mouse models.