The current study is based on Self-Determination Theory to examine the direct and indirect effects of excessive social networking sites usage among Arab university students and its impact on their digital identity and digital citizenship. A comparative correlational approach was employed, with a questionnaire used as the data collection tool from a sample of 363 students from Arab universities (Egyptian and Iraqi). The results revealed that students at Arab universities engage in excessive use of social networking sites, spending a "relatively large" amount of time on them. This behavior was reflected in their adoption of a mixed digital identity (both real and borrowed), and they demonstrated a relatively "high" level of digital citizenship. However, the order of the dimensions that constitute digital citizenship varied between students from the two countries. In a related context, it was found that the intensity and experience of the respondents' use of social networking sites did not affect their digital identity. Similarly, students' digital citizenship did not influence their digital identity. On the other hand, the digital characteristics of social networking sites users had a positive impact on their digital identity. Furthermore, it was confirmed that digital citizenship positively affected the digital characteristics of users. Additionally, the intensity and experience of the respondents' use of social networking sites did not influence their level of digital citizenship.