Academic stress is a pervasive phenomenon among university undergraduates globally, generating cascading effects on psychological wellbeing, sleep architecture, and scholastic performance. This cross-sectional study examined the prevalence and severity of perceived academic stress among 2,847 undergraduate students enrolled across five faculties of the University of Strasbourg using the Perceived Stress Scale (PSS-10), and investigated its associations with depression symptoms (PHQ-9), generalised anxiety (GAD-7), quality of life (WHOQOL-BREF), sleep duration and quality (Pittsburgh Sleep Quality Index), and cumulative grade point average.Structured cluster sampling stratified by faculty and year of study was employed. Results revealed that 38.4 percent of participants met criteria for high perceived stress (PSS-10 above 27), with first-year students and those in medical and competitive professional programmes showing the highest prevalence. High-stress participants demonstrated significantly lower GPAs (mean 2.74 vs. 3.61 in low-stress controls), shorter sleep duration (mean 4.8 vs. 7.4 hours), and markedly elevated PHQ-9 and GAD-7 scores. Multiple regression analysis identified examination frequency, financial insecurity, social isolation, and poor sleep quality as independent predictors of PSS-10 score, with examination frequency accounting for the largest proportion of explained variance.Mediation analysis indicated that sleep quality partially mediated the relationship between perceived stress and academic performance, explaining 31.4 percent of the total stress-GPA association. The findings provide a quantitative evidence base for targeted university mental health interventions, advocating for restructured examination scheduling,