Purpose: Physical behaviors, including physical activity, sedentary time, and sleep, are associated with health and together comprise the 24-hour day. Among working-aged adults, the composition of these 24-hour physical behaviors may vary across occupations, but the extent of these differences remains unknown. This population-based study examined how the composition of 24-hour physical behaviors differs in working-aged adults across occupational groups during work and leisure time. Methods: The study population consisted of 2,809 adults from the Northern Finland Birth Cohort 1966 46-year follow-up study, who wore a hip-worn accelerometer for 14 days. The accelerometry data was combined with self-reported diaries to determine time in bed and work hours. Four occupational groups were aggregated based on occupation type and occupational skill level: high-skill white-collar, low-skill white-collar, high-skill blue-collar and low-skill blue-collar. Time spent on physical behaviors during workdays (including working hours and leisure time separately) and non-workdays were calculated. Differences in physical behavior compositions were assessed using a compositional data analysis approach based on log-ratios of geometric means, with the low-skill blue-collar group as the reference group. Results: Significant differences in 24-hour physical behaviors across occupational groups were mainly observed during workdays. During workday working hours, all other occupational groups had less physical activity (both moderate-to-vigorous and light-intensity physical activity) compared to the reference group. During workday leisure time, significant differences were observed in all physical behaviors, except for sedentary time. On non-working days, the high-skill white collar group had higher moderate-to-vigorous physical activity compared to the reference group. Conclusions: The composition of domain-specific 24-hour physical behaviors differs across occupational groups, particularly during workdays.