Intellectual disability (ID) is one of neurodevelopmental disorders characterized by a limitation in intellectual functioning and adaptive behavior. The prevalence of ID is as relatively high as several percent of the population. Genetic factors as well as environmental factors play an important part in ID, and a significant number of candidate disease-associated genes have been identified. However, given clinical and genetic heterogeneity, the cellular and molecular mechanisms of ID remain largely unknown. Among candidate disease-associated gene products, Chromosome alignment-maintaining phosphoprotein 1 (CHAMP1), which was originally identified a regulator of kinetochore-microtubule attachment, is involved in neuronal development. Importantly, CHAMP1 is one of the most recurrently mutated genes in patients with ID. To explore the pathological roles of CHAMP1 in ID, we generated a mouse model heterozygous for a CHAMP1 mutation identified in a patient with ID and identified impaired fear memory formation in the mice. Our results provide insight into how disease-associated mutations on CHAMP1 lead to impaired memory formation, which underlies the pathogenesis of ID.