The arbor vitae /ˌɑːrbɔːr ˈvaɪtiː/ (Latin for "tree of life") is the cerebellar white matter, so called for its branched, tree-like appearance. In some ways it more closely resembles a fern, and is present in both cerebellar hemispheres. The pattern is most apparent on a midsagittal section of the cerebellum.

The arbor vitae forms the central white-matter core of the cerebellum and serves as a conduit for pathways that carry sensory and motor information to and from the cerebellar cortex. It is continuous with the cerebellar white-matter tracts entering and leaving the cerebellum through the cerebellar peduncles.

Within the arbor vitae, the deep cerebellar nuclei: the dentate, globose, emboliform and the fastigial nuclei are situated. These nuclei give rise to the major output (efferent projections) of the cerebellum to other parts of the nervous system.