Amyotrophic lateral sclerosis (ALS) is a rapidly progressive, fatal neurodegenerative disease characterised by the loss of upper and lower motor neurons. Approximately 10% of ALS cases have a known family history of the disease and mutations in multiple genes have been identified. ALS-linked mutations in CCNF were recently reported, however the pathogenic mechanisms associated with these mutations are yet to be established. To investigate possible mechanisms, an in vitro model of ALS was developed that expressed mutant CCNF in a neuronal cell line (Neuro-2a). Proteomic analysis of this in vitro model identified the disruption of several cellular pathways, including those associated with caspase-3 mediated cell death and axonal outgrowth. To establish whether these findings were replicated in vivo, a zebrafish model was developed. Transient overexpression of human mutant CCNF in zebrafish led to increased caspase-3 activity, increased cell death and a motor neuron axonopathy consisting of shortened primary motor axons and increased frequency of aberrant axonal branching. A significant correlation between the severity of this mutant CCNF-induced axonopathy and reduced motor function was also demonstrated in this model, with zebrafish expressing the mutant protein demonstrating an impaired motor response to a light stimulus. This is the first report of an ALS-linked CCNF mutation in vivo and indicates that zebrafish will be a useful tool to model the pathogenesis of CCNF-linked motor neuron degeneration.