For several years, the number of studies on the links between excessive mobile phone use and mental health has been increasing. The aim of the study was to establish if there is a relationship between mobile phone addiction and depression in university students and if phubbing is a mediator of this relationship. The authors also tested if this mediation effect was moderated by loneliness and if the model of relationships between these variables was the same in women and in men. The participants were 402 university and college students from Ukraine, aged 17 to 31; 74% of them were women. The authors used the Adapted Mobile Phone Use Habits, the Phubbing Scale, the Center for Epidemiologic Studies Depression Scale, and the Loneliness Scale. The results of the study have shown that higher mobile phone addiction and higher phubbing is associated with a higher level of depressive moods, with phubbing functioning as a mediator of the relationship between mobile phone addiction and depression. A moderator of this mediation is loneliness, the moderation effect being asymmetrically dependent on gender: in men, high loneliness increases the mediating role of phubbing, which more markedly translates into depression, while in women the analyzed mediation effect becomes weaker with an increase in the sense of loneliness (phubbing correlates less strongly with depression).