Objective Despite the availability of mental health care, only a minority of depressed adolescents and young adults receive treatment. This study aimed to investigate facilitating factors and barriers in help-seeking behaviour of adolescents and young adults with depressive symptoms, using qualitative research methods. Methods In-depth, semi-structured interviews with 32 participants with current or previous depressive symptoms aged 16 to 24 years using thematic content analysis. Findings Our sample consisted mainly of adolescents who eventually found their way to professional help. Five main themes in help-seeking by adolescents and young adults were identified: (I) Individual functioning and well-being, (II) Health literacy, (III) Attitudinal aspects, (IV) Surroundings, and (V) Accessibility. Prompts to seek treatment were disease burden and poor academic performance. Health illiteracy negatively influenced treatment-seeking behaviour. Attitudinal aspects either hampered (shame, wanting to handle the problem oneself, negative attitudes towards treatment) or facilitated (positive attitudes towards treatment) help-seeking. Furthermore, adolescents’ surroundings (school, family, and peers) appeared to play a critical role in the recognition of depressive symptoms and encouragement to seek help. Barriers regarding accessibility of mental health care were found, whereas direct and easy access to treatment greatly improved mental health care use. Conclusion Facilitating factors can play a critical role in the help-seeking process of depressed adolescents and young adults, and may guide efforts to increase access to mental health care of this vulnerable age group. In particular, recognition and encouragement from school personnel and peers and easy access to care providers positively influenced help-seeking in our sample. Health illiteracy and attitudinal aspects appeared to be important barriers to seeking treatment and public/school campaigns aimed at reducing health illiteracy and stigma might be necessary to improve treatment-seeking and health care utilization in this age group.