The fundamentals of urban planning suggest that accessibility to public open spaces, particularly the parks, is supposed to contribute to the increased use of them. Accessibility is a difficult and complex concept to define and measure. Moreover, literature review shows few researches have defined the concept of accessibility from the perspectives of potential park users and its influence on individuals' behavior. This study aims to define factors adolescents find important in perceiving whether a park is accessible and the influence of accessibility on the use of urban parks for adolescents aged 15-18. This qualitative study's findings are based on interviews with a group of 17 male and female adolescents. The findings show that the perception of the accessibility concept among adolescents is an outcome of different parameters such as proximity, travel time, presence/non-presence of traffic, availability of transportation, etc. The results of this study contribute to enhancing the understanding of the accessibility concept as a multi-dimensional construct from adolescents' point of view, and its influence on the use of parks.