Background: Little is known about the development of anxiety symptoms from late childhood to late adolescence. The present study determined developmental trajectories of symptoms of separation anxiety disorder (SAD), social phobia (SoPh), generalized anxiety disorder (GAD), panic disorder (PD), and obsessive-compulsive disorder (OCD) in a large prospective community cohort. Methods: Anxiety symptoms were assessed in a community sample of 2220 boys and girls at three time-points across a 5-year interval. The Revised Child Anxiety and Depression Scale (RCADS) was used to assess anxiety symptoms, and multilevel growth-curve analyses were performed. Results: All subtypes of anxiety first showed a decrease in symptoms (beta for age ranged from -0.05 to -0.13, p less than 0.0001), followed by a leveling off of the decrease, and a subsequent slight increase in symptoms (beta for age-squared ranged from 0.006 to 0.01, p less than 0.0001) from middle adolescence (GAD, SoPh, SAD) or late adolescence (PD and OCD) onwards. This increase in anxiety symptoms could not be explained by a co-occurring increase in depression symptoms. Girls had more anxiety symptoms than boys, and this difference remained stable during adolescence (p less than 0.0001). Gender differences were strongly attenuated by adjustment for symptoms of depression. Conclusions: The current study shows that, in the general population, anxiety symptoms first decrease during early adolescence, and subsequently increase from middle to late adolescence. These findings extend our knowledge on the developmental course of anxiety symptoms during adolescence. This is the first study to separate the development of anxiety symptoms from that of symptoms of depression.