Developmental absence (agenesis) of the corpus callosum (AgCC) is a common brain malformation that presents in isolation or in association with other conditions. Variability in aspects of neuropsychological functioning has been reported in small samples of individuals. This study aimed to systematically review the literature to characterize the profile and severity of cognitive impairments in individuals with AgCC across development. A mean general intellectual ability was calculated and neuropsychological functioning was qualitatively examined. We discuss methodological limitations of the literature, inherent heterogeneity of the causes and comorbidities of AgCC, and the developmental aspect of AgCC in opposition to "split-brain patients."