A review of twin research on reading and spelling disabilities fulfills two key functions: First, the special educational and developmental concerns of twins are highlighted. Second, the value of twin studies for investigating genetic and environmental factors underlying learning disabilities in a variety of cognitive domains is demonstrated. The discussion is introduced by a review of biological aspects of twinning and descriptions of twin research designs. Findings from twin studies that have addressed the unique educational circumstances, and the genetic effects of multiple‐birth children, on reading and spelling difficulties are then summarized. These findings are considered with reference to the professional activities of teachers and specialists in reading and language skills. Resources for assisting exceptional twin children are listed.