Objectives This study aimed at disentangling the effects of overtime hours from those of long workhours. For part-time workers, overtime work is not intertwined with long workhours as it is for full-time workers. Therefore, part-time and full-time employees were compared with regard to the association between overtime and well-being (fatigue and work motivation). Such comparisons may also shed more light on the psychological meaning of overtime work for part-time and full-time workers.

Methods A survey study was conducted among a representative sample of Dutch employees (N=2419). An analysis of covariance was used to investigate whether the relationship between overtime and well-being differs between marginal part-time (8–20 contractual workhours), substantial part-time (21–34 hours), and full-time (≥35 hours) workers. Work characteristics (ie, job demands, decision latitude, and job variety), age, and gender were treated as covariates.

Results No significant relationship between overtime and fatigue was found for any of the contract-hour groups. For the part-time workers, overtime was not related to higher work motivation, whereas for full-time workers it was.

Conclusions It is important to distinguish between overtime and long workhours, given the differential overtime–motivation relationship among part-time and full-time workers. This finding suggests that part-time employees work overtime for reasons other than motivation or that working overtime does not enhance work motivation for this group of employees. Overtime work seems to have a different meaning for part-time and full-time workers.

Key terms fatigue; full-time worker; job characteristics; long workhours; overtime; part-time worker; work motivation