Two systems, the circadian clock, and the stress response mechanism are key to adjusting and maintaining the body’s dynamic balance. The influence of glucocorticoid-mediated stress in the circadian synchronization of the endocrine function of adult rats Leydig cells monitored through various in vivo and ex vivo experimental models. The experimental models included the application of stress by immobilization (IMO), at different circadian times, and with a different number of repetitions, as well as the treatment with the use of synthetic glucocorticoids. Specifically, these studies are designed to examine (1) are the effects of glucocorticoids on the pattern of clock gene expression, steroidogenesis-related genes, and other genes relevant to Leydig cell endocrine function time-dependent, and (2) are the effects dependent on the type of stressful event (acute and recurrent stress). In the analyzed experimental models, it was found that stress generally increased glucocorticoid levels and decreased blood testosterone levels. However, it was noticed that the effect of repeated stress on the level of testosterone in the blood was the least pronounced in the dark (active) phase of the day. Transcriptional analysis of genes revealed different susceptibility to stressful events depending on circadian time: most genes associated with steroidogenesis (Lhcgr, Nr3c1, Cyp11a1, Cyp17a1, Hsd3b1/2) showed reduced expression in the inactive (light) phase, while in the active dark) the phase of the day, their expression unchanged or even stimulated. Stress also affected the expression of clock genes and proteins and stimulated the expression of Bmal1/BMAL1, Per1/2/PER1. Treatment of rats with synthetic glucocorticoids showed a similar response as IMO treatment. Principal component analysis (PCA) showed no significant differences between treatments, especially on Per1 and Rev-erb. These results were confirmed by ex vivo treatment of Leydig cells with Hydrocortison and a glucocorticoid receptor blocker. The results indicate that the effect of the glucocorticoid component of the stress response on Leydig cell activity depends on the time and type of stress, emphasizing the importance of circadian activity in supporting and maintaining androgen homeostasis, and male fertility.