Health professions educators seek understanding of the process of learner performance and achievement. Grit, defined as passion and perseverance for long-term goals, has been implicated in this process. Research suggests that effort counts twice in achievement: skill times effort equals skill and, subsequently, skill times effort equals achievement. Research also suggests that an individual's interest influences job performance and satisfaction. Grit, composed of Perseverance of Effort and Consistency of Interest, has been shown to positively correlate with performance and achievement in various disciplines. Limited research reveals Grit negatively correlates with resident attrition and physician burnout. This study evaluates relationships between Grit and medical student performance measures. We gather validity evidence for Grit scale use among medical students and, subsequently, use this data to evaluate for differences in Grit score by gender and assess whether there is a relationship between Grit and standardized exam scores. We hypothesize that Grit will not vary with gender and that it will be positively associated with standardized examination scores. Enrolled students receive the 12-item Grit survey. An exploratory factor analysis evaluates validity evidence of Grit. Descriptive statistical analysis, Pearson correlation, and moderation analysis evaluate if Grit score differs by gender and if there are relationships with standardized exams. The survey response rate is 59% (412/698) and exploratory factor analysis replicates the two-factor structure of Grit found in other fields-Perseverance of Effort and Consistency of Interest. Average Grit scores do not significantly differ by gender. Grit weakly correlates with United States Medical Licensing Exam Step 1 (r = 0.10, = 0.36) and United States Medical Licensing Exam Step 2 Clinical Knowledge (r = 0.12, P=0.29). Grit weakly and negatively correlates with Medical College Admission Test score (r = - 0.18, P<0.05). Grit is not a significant moderator of the relationship between Medical College Admission score and Step exams scores. Exploratory factor analysis results provide preliminary validity evidence for Grit scale use in medical students. Grit does not significantly moderate the Medical College Admission Test-Step score relationship. Grit correlates negatively with Medical College Admission Test scores. Though the correlations in this study were not significant, the results showed that Grit may tend to positively correlate with Step 1 and Step 2 Clinical Knowledge examinations. Given that these three exams are taken at different levels of training, the stepwise progression towards positive correlation may suggest that the theory "effort counts twice" applies to medical training.