This study aimed to examine the joint association of daily rest period (DRP) and sleep duration with occupational stress and sickness absence in Japanese daytime employees. This study utilized a web-based cross-sectional survey conducted in February 2022. The 13,306 participants reported their DRPs and sleep duration. Occupational stress was assessed using the New Brief Job Stress Questionnaire, while the frequency of sickness absence was measured using a 4-point Likert scale. The participants were categorized into 14 groups based on their DRPs and sleep duration. Logistic regression analyses revealed that the combination of a short DRP and normal sleep duration, as well as the combination of an adequate DRP and short sleep duration, were significantly associated with high occupational stress compared to the reference group (adequate DRP and normal sleep duration). These results indicate that not only normal sleep duration but also sufficient DRPs are important for reducing occupational stress. However, only the combination of a short DRP and normal sleep duration, and not the combination of an adequate DRP and short sleep duration, were significantly associated with a lower frequency of sickness absence. This may be owing to the possibility that employees with a short DRP (indicating longer working hours) are too busy to take leave even when they are sick.