BackgroundNursing labor organization is consequential to many stakeholders, but collective evidence for outcomes associated with nurse unionization is lacking. PurposeTo synthesize evidence of associations between nursing unions and nurse, patient, and system outcomes. MethodA scoping review. FindingsTwenty-four articles spanning nearly 50 years were abstracted. Most studies (n=16; 67%) included nurse outcomes, usually remuneration (n=10; 42%). Patient and systems outcomes were less common (for each: n=7; 29%). Union wage premiums were modest. Evidence for other nurse outcomes (e.g., job satisfaction, retention) was limited and mixed. Unionization was associated with improvements in many but not all patient outcomes studied, and with operational differences, including decreased staffing and labor substitution. DiscussionCollective bargaining outcomes may help administrators understand nurses’ needs and concerns and thereby improve nurse recruitment and retention. For example, modest wage effects may signal non-wage priorities among nurses, which are understudied and worthy subjects of future research.