Health systems often implement innovative quality improvement and patient safety initiatives, but the longevity and sustainability of these initiatives remains a challenge. This scoping review explored the factors which enable and hinder sustainability of hospital-wide quality improvement (QI) initiatives. Three overarching themes were identified – the role of (1) people, including the organizational and leadership teams, as well as frontline staff implementing the QI initiatives, (2) processes, such as local and organizational integration and planning for sustainability, and (3) the organizational environment such as resources, infrastructure, and hospital culture.