Background Medical education is considered one of the toughest college degrees to acquire. Exploring the factors that determine good academic performance in medical school will help in the planning of curriculum and assist students to navigate through medical school more effectively. Methods This cross-sectional and descriptive study enrolled 145 second year clinical students (500 level) of the Enugu State University of Science and Technology in south-east Nigeria using purposive and convenient sampling method. It assessed factors that predicted good academic performances in surveyed students. Results Medical students without membership in any campus group, those that receive(s) less than ten thousand naira (≈US$27) every month as upkeep allowance, those admitted through the University Matriculation Examination, and students who visit their families on a weekly basis were more likely to have better academic performances than those in corresponding categories. Of these significant predictors of good academic performance, mode of admission into medical school ( Rs =−0.310 P =0.001) and monthly allowance students got for upkeep ( Rs =−0.281 P =0.001) had the strongest correlation with good academic performances. Conclusion Our study identified factors that correlate with academic performances among medical students. We propose frequent appraisal of these factors and support system that will help improve performance in these students.