Abstarct: Background and Purpose: Hormonal responses to exercise are among the most important determinants of physiological adaptations in athletes. Among various hormones, testosterone and cortisol have received considerable attention in sports science because of their key roles in regulating anabolic and catabolic processes. Caffeine is one of the most widely used ergogenic aids in sport and may also influence hormonal balance. Therefore, the purpose of the present study was to investigate the effect of caffeine supplementation on the testosterone-to-cortisol ratio following exhaustive exercise in university athletes. Methods: In a randomized, double-blind, crossover design, 13 trained men completed two experimental conditions: caffeine supplementation (4 mg·kg⁻¹ body mass) and placebo. In each session, participants consumed either caffeine or placebo and subsequently performed an exhaustive exercise test. Blood samples were collected before supplementation and immediately after exercise. The exercise trials were conducted one week apart and at the same time of day. Data were analyzed using the Shapiro–Wilk test and repeated-measures analysis of variance, with the significance level set at p < 0.05. Results: The findings indicated that caffeine supplementation had no significant effect on serum testosterone levels but significantly increased cortisol concentrations (p < 0.05). In addition, exhaustive exercise significantly elevated both serum testosterone and cortisol levels (p < 0.05). A significant difference between the caffeine and placebo conditions was observed for the cortisol response to exercise (p < 0.05). Furthermore, caffeine intake at rest did not significantly affect the testosterone-to-cortisol ratio, whereas exhaustive exercise resulted in a significant reduction in this ratio (p < 0.05). Conclusion: Acute caffeine ingestion induced a modest increase in cortisol concentration and enhanced the cortisol response to exhaustive exercise. However, the magnitude of these changes was insufficient to significantly alter the testosterone-to-cortisol ratio. These findings suggest that the hormonal response to caffeine and intense exercise is primarily influenced by activation of the hypothalamic–pituitary–adrenal (HPA) axis.