The social media app TikTok is heavily used by young people worldwide and is also very popular among Swiss young people. However, the app has been criticised for its low level of data protection, prompting the app provider Bytedance to step up its efforts in this area (e.g. function restrictions for people under 16). This qualitative study aimed to investigate what knowledge Zurich pupils have about data protection in TikTok and how they protect their personal data in everyday life. In this way, the study formed a first contribution to the design of corresponding educational materials and for a later intervention.