Problematic Internet use (PIU) has been posited as the negative outcome of unmet psychological needs in real life. The present study, relying on the cognitive-behavioral model of PIU (Brand, Young, & Laier, 2014; Davis, 2001) and self-determination theory (Deci & Ryan, 2000), investigated the extent to which coping strategies in aversive situations and mindfulness during Internet use serve as mediating mechanisms in the relation between need satisfaction and generalized PIU (GPIU; dependency on multiple functions of the Internet). Path analysis on a sample of 165 Turkish early adolescents (Mage = 12.88, SD = .83; 49.1% females) found that need satisfaction was negatively related to PIU via low avoidant coping and high mindfulness in Internet engagement. The findings support the pathways from disadvantageous social context to GPIU suggested by Brand and colleagues’ (2014) model of GPIU and additionally show that next to avoidant coping, online mindfulness, an indicator of loss of cognitive control, can be a proximal correlate of GPIU. Interventions for adolescents’ harmonious Internet use could focus, among others, on adolescents’ need satisfaction, awareness of coping strategies, and development of online mindfulness.