The aim of our study is to concurrently examine, within the same structural model, the effects of social cognitive functions, empathy, emotional regulation difficulties, interpersonal competence and smartphone addiction on adolescents who display phubbing behavior and those who are being phubbed. A cross-sectional study was carried out with the participation of 305 adolescents between the ages of 16 and 18. The Difficulties in Emotion Regulation Scale—Short Form, Interpersonal Reactivity Index, Interpersonal Competence Scale, Generic Scale of Phubbing and Generic Scale of Being Phubbed, Smartphone Addiction Scale and Reading the Mind in the Eyes Test were administered to the participants. Smartphone addiction was positively associated with phubbing behavior (β = 0.775, p < 0.001), whereas interpersonal competence was negatively associated with phubbing (β = −0.145, p < 0.001). A significant positive indirect association between emotional regulation difficulties and phubbing behavior via smartphone addiction was observed (β = 0.273, p < 0.001). Interpersonal reactivity was positively associated with being phubbed (β = 0.203, p = 0.001), whereas social cognition was not significantly associated with either outcome. Our findings suggest that different socio-cognitive competencies and smartphone addiction may be associated with phubbing in adolescents, and that these associations may differ between phubbing behavior and being phubbed.