The aim of this study is to research the mediational role of smartphone addiction on relationship between nomophobia and aggression level of university students. The data collected through the convenience samples over the Internet has reached a wider audience. The study group consisted of 307 university students. Smartphone Addiction Scale Short Form, Buss Perry Aggression Scale and Nomophobia Scale were used during the research process. In addition, Relational survey method used, and mediation model of Baron and Kenny's was used to analyze the mediation effect of smartphone. Smartphone usage is related to nomophobia and anger. Partial mediation effect of smartphone addiction was proved among nomophobia and anger. On the relation between aggression and nomophobia, the smartphone indirect effect value is %6.