Distinct patterns of cerebellar atrophy between different forms of frontotemporal dementia (FTD) have been identified for the first time in an MRI study. A total of 96 patients with FTD participated in the study; 45 had behavioural-variant FTD (bvFTD), 28 had semantic dementia (SD) and 23 had progressive nonfluent aphasia (PNFA). Structural MRI was used to assess whole-brain and cerebellar grey matter integrity, and the structural findings were assessed alongside cognitive performance. Bilateral grey matter atrophy was observed in all FTD subtypes, but the patterns differed and atrophy was greatest in bvFTD. The loss of cerebellar grey matter was associated with impairment of different cognitive functions in different FTD subtypes: attention and working memory in bvFTD, visuospatial cognition in SD, and language and motor cognition in PNFA. The findings demonstrate that cerebellar atrophy is syndrome-specific in FTD, rather than a result of global atrophy, and that this atrophy contributes to cognitive dysfunction in these disorders.