Objective Social media usage is considered one of the most common activities among university students that could impact their daily lives. There is a great variation of the level of this impact depending on gender and some other factors. The impact of social media usage on academic performance is not known. This study aims to evaluate gender differences amongst students at the University of Sharjah (UoS) for predicting the impact of social media usage on their academic performance. Methods A cross-sectional study was conducted on 328 medical UoS students across all years of study. Social media usage was assessed by a self-administered questionnaire titled Social Media and Academic Performance of Students Questionnaire (SMAAPOS). This tool used a 4-point Linkert rating scale and contained two sections: a section for participants' demographics, year of study and time spent on social media and another section collected participants' views about the impact and addictiveness of social media. Chi-square test using SPSS (v 20) was used for data analysis. Results Of the 500 invitees, 328 students responded; a response rate of 66%. The respondents were 61% female and 39% male students. The average time spent on social media usage was reported as 2–3 h per day. Furthermore, males were more addicted to social media than females (49.6%) and (32%), respectively. Additionally, females' academic performance was more highly influenced by the usage of social media than that of males, although males were more addicted to social media networks. Conclusion This study demonstrates a significant difference in the academic performance of medical students as influenced by social media usage. Medical educators are urged to frame guidelines for using social media for educational purposes that will help improve the academic performance of the students.