Abstract Study Objectives Relief from work stress has been hypothesized to explain improvements in sleep duration and quality following retirement, but this has not been confirmed with longitudinal studies. By using repeat sleep data, we examined the role of removal of work-related stressors in changes in sleep at retirement. Methods The study population consisted of 2,053 participants from the Finnish Retirement and Aging study. Participants’ sleep duration, sleep difficulties (difficulties falling asleep, difficulties maintaining sleep, waking up too early in the morning, nonrestorative sleep), daytime tiredness, and sleep loss due to worry were assessed using surveys conducted once a year before and after retirement (average number of repeat surveys 3.5 [range 2–5] per participant). We used Poisson regression with generalized estimating equations to examine the associations between work-related stressors (job strain, low work time control, effort–reward imbalance, and organizational injustice) and changes in sleep at retirement. Results An increase in sleep duration and decrease in waking up too early in the morning, nonrestorative sleep, daytime tiredness, and sleep loss due to worry were observed shortly after retirement. No systematic associations across the work-related stressors and changes in sleep characteristics were observed. Higher number of work-related stressors before retirement was not associated with a greater magnitude of favorable changes in any of the postretirement sleep characteristics investigated. Conclusions This longitudinal study suggests that perceived sleep improves shortly after retirement and that these changes are mainly driven by factors other than relief from work stress.