Extracurricular activities are an important part of the school curriculum and should reflect students' interests and aspirations. Schools have a duty to provide a range of content and activities that can be enjoyed in students' free time, and it is the duty of teachers to organise and supervise these. Pupils can participate according to their personal interests, wishes and preferences, and their participation contributes to the development of their competences, skills and personalities. According to the concept of positive youth development, young people who develop in a supportive environment are likely to fulfil their potential and use the positive outcomes to contribute to the well-being of their families, society and their own lives. The 5C model is used in this case study as a guide for analysing the contribution of extracurricular activities to students' positive development. The aim of the study is to gain insight into students' awareness and opinion of extracurricular activities at their school in order to assess the quality and match of extracurricular activities with students' developmental needs. A qualitative study was conducted with the participation of five high school students from Zagreb. The results show that extracurricular activities contribute significantly to the positive development of students, provided that they are informed in good time about the opportunity to participate and that they are implemented in a high-quality manner. The contribution of extracurricular activities to the development of competences, better relationships and students' self-confidence is universal, while the contribution to the development of character and caring is more related to the content and purpose of the extracurricular activities.