Aims: To explore physical activity (PA) habits among the medical students and examine the correlation with their grade point average (GPA) achievement at College of Medicine, King Saud University, Riyadh, Saudi Arabia.Methods: A cross-sectional study was conducted among the medical students (n = 409), during the academic year 2012–2013. Students’ physical activity habits were self-reported. GPA, body mass index (BMI) and body fat percent (BF%) were collected and analyzed with SPSS software.Results: Out of 409 students, 193 (47.2%) students reported being physically active. Our result showed a significant positive association between students’ PA habits and high-GPA achievement (χ2 = 10.65, p = 0.001). The greatest odds ratio of high GPA was found among the fourth year students (OR = 3.08, CI: 1.15–8.28, p = 0.025) and fifth year students (OR = 5.07, CI: 1.48–17.31, p = 0.010). In addition, significant association was found between the normal BMI and high-GPA achievers (χ2 = 8.30; p = 0.016). However, no statistically, significant association was found between BF% and GPA.Conclusions: The present study showed a positive associations was found between PA habits and high academic achievement. In addition, positive association was found between PA, obese students and GPA achievement. Therefore, there is a need for the establishment of physical activity education and public health programs to promote importance of PA in Saudi population.