Anxiety sensitivity, a belief that symptoms of anxiety are harmful, has been proposed to influence development of panic disorder. Recent research suggests it may be a vulnerability factor for many anxiety subtypes. Moderate genetic influences have been implicated for both anxiety sensitivity and anxiety, however, little is known about the aetiology of the relationship between these traits in children. Self-reports of anxiety sensitivity and anxiety symptoms were collected from approximately 300 twin pairs at two time points. Partial correlations indicated that anxiety sensitivity at age 8 was broadly associated with most anxiety subtypes at age 10 (r=0.11-0.17, p<0.05). The associations were largely unidirectional, underpinned by stable genetic influences. Non-shared environment had unique influences on variables. Phenotypic results showed that anxiety sensitivity is a broad predictor of anxiety symptoms in childhood. Genetic results suggest that childhood is a developmental period characterised by genetic stability and time-specific environmental influences on anxiety-related traits.