This study aimed to highlight the contribution of self-efficacy, optimism, resilience and perceived stress on academic performance (GPA) at medical undergraduate students. Additionally, we investigated the relationship established between abovementioned variables, gender and position in the academic cycle and the factors associated with satisfaction regarding own academic results. 118 students (25 men, 93 women, mean age 22.863, SD = 1.763) participated in the study. They were administered the General Self-Efficacy Scale (G-SES), the Revised Life Orientation test (LOT-R), the Brief Resilience Scale (BRS) and the Perceived Stress Scale (PSS). t, Wilcoxon-Mann-Whitney, chi-square tests, and linear regressions were performed, in order to test the strength of the hypothesized associations. Data analysis demonstrates a significant association between low optimism, low resilience, high perceived stress and poor academic performance. Even though preclinical students displayed greater perceived stress, it negatively correlated to GPA only in clinical students, this indicating a possible accumulation of stress-related effects. No gender differences were met for the studied variables. Students in clinical cycle were significantly less satisfied about their own performance. These results indicate solid associations between psychosocial variables and academic performance, and differences in the subjective evaluation of own performance, suggesting key points to address, when designing interventions against academic stress.