Given the importance of sleep to an individual's health and well-being, relatively little research has been conducted in the management and organizational behaviour literature on the relationship between sleep and work behaviour. Using spillover/crossover theory, we extended the current literature by investigating the possible supervisor-subordinate sleep relationship and introduced a serial mediation mechanism to answer how a supervisor's poor night's sleep translates into his/her subordinate's poor night's sleep. We conducted an experience sampling study involving 101 supervisors and subordinates over five consecutive working days (N = 505 occasions). Results verified that the spillover effect of supervisors' poor sleep on their next-day abusive supervisory behaviour has a crossover effect on their subordinates' poor sleep. Finally, results indicated that subordinate's physical exercise has the capacity to mitigate the influence of abusive supervision on subordinate' poor sleep. Future research should continue to examine the supervisor-subordinate sleep relationship and identify interventions in both the work and non-work domains of supervisor and subordinates as avenues for improving sleep health.