Digital technologies and the Internet constitute an indispensable part of children and adolescents’ daily life. In this context, the influence of digital devices and Internet usage on children and adolescents has emerged as a broad research field. Particularly, the impact of social networks has surfaced as a prominent research question, focusing also on how social media and influencer marketing influence children and adolescents’ consumer behaviour. Contributing to this literature, in this paper we present the qualitative research we conducted in Greece within the scope of the European Research Project DIGYMATEX. More specifically, we discuss the findings we collected through qualitative research concerning the online consumer behaviour of children and adolescences, especially in relation to the use of the Internet for market research and online shopping, and the impact that social media and influencers exert on the consumer behaviour. The data was collected through six focus groups with the participation of 23 children and adolescents, aged 9-18. Apart from contributing to the existing literature with findings from Greece, our study highlights the need for further research on the relationship between advertising literacy and self-regulatory mechanisms, considering also the element of gender, and the potential connection between digital maturity and advertising literacy.