The National Institute for Occupational Safety and Health Worker Well-Being Questionnaire (NIOSH WellBQ) provides an integrated assessment of worker well-being across multiple spheres, including individuals’ quality of working life, circumstances outside of work, and physical and mental health status. The questionnaire measures “worker” well-being as a holistic construct rather than simply “workplace” or “work-related” well-being. The NIOSH WellBQ is intended to help researchers, employers, workers, practitioners, and policymakers understand the well-being of workers and target interventions to improve worker well-being, among other applications.