Due to the notably increased penetration of smartphone use among university students and the alarming risk it poses to both physical and mental health, this study investigated mobile phone addiction among university students concerning student characteristics, mobile phone usage behaviors, and mobile phone use purposes and situations. The participants of this study were 600 university students, who were selected according to the convenience sampling method from different departments in Türkiye. The data were collected using the student characteristics form and the Mobile Phone Addiction Scale. The correlational research method was followed in the study. The data were analyzed using descriptive and inferential statistics. The results showed that students clustered as addicted and non-addicted had different mobile phone use behaviors on account of daily smartphone use duration, internet use duration on a smartphone, and daily smartphone check frequency. Being a female at a lower grade level and using mobile phones mostly at night made students more vulnerable to mobile phone addiction. Additionally, the results indicated a significant positive moderate correlation between internet use duration, daily smartphone use duration, daily smartphone check frequency, and mobile phone addiction scores. Lastly, checking social media apps, messaging, and editing photos significantly contributed to mobile phone addiction scores. Among the mobile phone use situations, when getting bored, during lessons, when watching TV or movies, and when being alone significantly contributed to mobile phone addiction scores. This study provided a thorough discussion and a set of recommendations.