Organizations are increasingly adopting “just-in-time” scheduling practices, which allows organizations to rapidly adjust staffing to meet fluctuating marketing demands. However, the impact of unstable work schedules on employee outcomes remains understudied, despite organizations increasingly adopting these scheduling practices to improve performance. Drawing on the meaning-making model, this paper examines how work schedule instability influences employee well-being and work-related outcomes. Employing a field study with data collected from multiple sources and time points, we found that work schedule instability can lead to workplace fatigue, which in turn lead to heightened insomnia and reduced work engagement and task performance. Further, work meaningfulness can buffer the negative impact of work schedule instability on employee well-being and work outcomes. These findings provide critical insights to research on work schedule instability and offer practical implications to scheduling practices.