The aims of this retrospective case series were to investigate whether twins born with craniosynostosis mirrored each other regarding operative surgery performed, age of undertaking surgery; outcomes in speech, language, and developmental milestones and what environmental factors were present for each set of twins.Case selection was based on clinical and radiographical evidence of craniosynostosis amongst twin sets. The twin sets included were those with craniosynostosis who had different sutures affected or those with the same suture affected but with a varying degree of severity.The presence of the following factors may have played an influential role in the clinical presentation of the twins; these were as follows: a maternal history of smoking, breech presentation, and genetic mutations. It was notable that the overall outcomes for the twins in this study were similar.These cases highlight the multifactorial nature in the development of craniosynostosis and how this influenced the phenotypic presentation of the twins.