The aim of this paper was to examine the prevalence of anxiety symptoms in adolescents. Additionally, it was also intended to determine whether there were any differences in the prevalence of anxiety symptomatology among the participants of the research in relation to gender and age. A survey was used that is part of the pilot project "The Positive Development of Adolescents in the City of Zagreb: Condition Analysis", conducted by the Faculty of Education and Rehabilitation Sciences of the University of Zagreb. The research was conducted in April and May 2017 and included three high schools in the city of Zagreb: First Gymnasium, Veterinary School and School of Graphic, Design and Media Production. For the purpose of the research, a battery of instruments of several scales was developed, of which the Demographic Data Questionnaire and the Anxiety subscale from The Depression, Anxiety and Stress Scale-21 (DASS-21) were used in this paper. A sample suitable for data processing consisted of 220 students aged 15 to 19. The collected data were processed using descriptive statistics methods in the SPSS Statistics 23.0 computer program. Research results showed that in more than half of the participants (55.56%) there is no anxiety symptomatology present or that it is present in moderate extent. At the same time, the prevalence of severe and extremely severe symptoms is present by 8.70% of the participants. The results also show that there are no differences in the prevalence of anxiety symptoms by gender, i.e. they are equally present in both girls and boys. Likewise, there was no difference in the prevalence of anxiety symptomatology with regard to age of the participants