Introduction: In this review article we outline the thinking and evidence behind our hypothesis that the problems suffered by dyslexic people may be attributable to cerebellar deficit. Method: Firstly, we provide an overview of recent evidence that proposes a central role for the cerebellum in cognitive skills, in particular those scaffolded by spoken language, in addition to its well-recognised role in motor skills. Secondly, we outline evidence from our laboratory that cerebellar function is abnormal in dyslexia. Results: We consider two specific lines of evidence: behavioral, and converging evidence from neuroimaging, which demonstrate significant differences between the dyslexic and control groups. We also apply the same battery of behavioural tests to a group of children who are non-discrepant poor readers. Discussion: Finally, we provide an ontogenetic causal chain for the development of dyslexia in terms of cerebellar deficit from birth, considering the implications of this framework for the key questions in dyslexia research. (Contains 1 figure.)