This study examines the links between employee perceptions of job insecurity, the work–nonwork interface, and stress‐related outcomes. Drawing on an adaptation perspective, we expect employees feeling greater job insecurity to engage in adaptive work behaviors including less use of work–nonwork support programs and greater willingness to let work permeate into one's personal life, which in turn will associate with greater work–nonwork conflict and emotional exhaustion. Data were collected from employees within a large energy company at 2 points in time. Results support the model, offering important insights into employee behavioral responses to job insecurity and key mechanisms through which insecurity may foster diminished employee well‐being.