A considerable amount of adolescents’ interpersonal communication takes place online. Adolescents use the internet to interact with friends and family, but also with people who were previously unknown to them. This study focuses on two types of interactions with unknown people from the internet: online communication and offline face-to-face meetings. We used theoretical frameworks of adolescent developmental tasks and risk-taking behavior to identify the psychological and social factors that relate to the likelihood that adolescents will interact with unknown people. We further examined the differences between the two types of interactions. Using a sample 6,647 adolescents, aged 11-16 (50.4% girls), from five European countries included in the EU Kids Online IV project, we examined the association of selected factors for both types of interactions. Our results support only some of our developmentally framed hypotheses – specifically, though age predicted both types of interactions, the quality of family relationships only predicted face-to-face meetings, and we found no association between the social support of friends and either type of interaction. In line with our risk-taking-framed hypotheses, sensation seeking, and emotional symptoms predicted both types of interactions; however, self-efficacy predicted only face-to-face meetings. Supporting our reasoning that online communications and face-to-face meeting are distinct behaviors, self-efficacy and the quality of family relationships predicted only face-to-face meetings, while disclosure in online communication only predicted online communication. Thus, future research and preventive efforts should be mindful of the differences and not conflate these behaviors. We also recommend preventive efforts for adolescents with elevated emotional symptoms who spend a lot of time online.