Researchers have argued that individuals who show self-restraint are more likely to show self-injurious behavior (SIB) that is compulsive. Self-injurious behavior, self-restraint, and compulsive behaviors have been described as features of Cornelia de Lange syndrome. We examined whether individuals with this syndrome displaying SIB and self-restraint exhibit more compulsive behaviors than do those without SIB and self-restraint. Main caregivers of individuals with the syndrome completed questionnaires. A significant association was found between SIB and self-restraint, and those displaying both behaviors displayed significantly more compulsions than did those not exhibiting them. Findings extend the compulsive behavior theory and highlight areas for further research.