The aim was to examine objectively measured sedentary behavior and mental health and quality of life across both week and weekend days in adults. There were significant differences in sedentary behavior across weekdays compared to weekends. Participants spent more time sitting and less time standing during the week compared to the weekend yet this was accompanied by a significantly greater step count. The increase in time spent sitting during weekdays could be attributed to occupation-related behavior within the sample as all of the participants worked at least 30 hours during the week in variable occupations. Our findings contradict those reported in the Health Survey England  where adults self-reported spending 4.8 hours being sedentary on weekdays and 5.3 hours at weekends. Yet it should be noted that the higher values of sedentary behavior reported in the current study could be due to the use of an objective method to assess sedentary behavior more accurately. Our findings are similar to those reported in a study by Thorp et al. . They assessed sedentary behavior objectively, comparing work days and non-work days, and found that on work days, participants spent 10.7 hours in sedentary activities yet 8.6 hours in sedentary activities on non-work days. These findings, along with those in the current study, provide support that the workplace could be a key setting for sedentary behavior and should be targeted for appropriate public health intervention strategies.