The cerebellum is a key region of the brain for motor control and cognitive functioning, and it is involved bidirectional communication with the cerebral cortex. As one of the smallest non-human primates, the common marmoset provides many advantages in the study of the anatomy and the functions of cerebello-cerebral circuits. However, the cerebellum of the marmoset is far from being well described in published resources. In this study, we present a comprehensive atlas of the marmoset cerebellum in three parts: 1) fine-detailed anatomical atlases and surface-analyzing tools of the cerebellar cortex, based on ultra-high resolution ex-vivo MRI; 2) functional-connectivity gradients of the cerebellar cortex, based on awake resting-state fMRI; and 3) structural-connectivity based mapping of the cerebellar nuclei, based on high-resolution diffusion tractography. The atlas shows the anatomical details of the marmoset cerebellum; reveals distinct gradient patterns of the intra-cerebellar and the cerebello-cerebral functional connectivity; and maps the topological relationship of the cerebellar nuclei in cerebello-cerebral circuits. As version 5 of the Marmoset Brain Mapping project, the atlas describes the anatomical and connectivity details of the marmoset cerebellum and is publicly available via marmosetbrainmapping.org. ### Competing Interest Statement The authors have declared no competing interest.