This study aimed to assess the risks and opportunities associated with Facebook usage and to explore the moderating role of psychosocial (mal)adjustment, nationality and age in these relationships. This correlational study involved a sample of 452 Brazilian and 500 Portuguese youths, aged between 14 and 20 years. Results showed that these youths spent a daily average of 61-120 minutes on Facebook, three to four times per week, displaying a positive attitude towards its use. These characteristics were most notable in the Brazilian youths [t(950) = 5.64, p < .001; t(950) = –5.07, p < .001; and t(950) = – 6.85, p < .001, respectively]. The Portuguese youths ran more risks than the Brazilians [t(950) = 6.36, p < .001], but both youths equally enjoyed the opportunities. In the case of the Portuguese youths, the risks and opportunities were moderated by the frequency of use, in other words “the higher the usage, the more risks and opportunities” (β = –.235 p < .001and β = –.167, p < .001, respectively). The psychosocial adjustment indicators did not moderate the effects of Facebook usage habits in risks and opportunities. The less psychosocially adjusted youths were those who ran more risks and also made the most of the opportunities. The results are discussed in light of the role of psychological, socio-cultural and developmental factors.