Objective: This qualitative study explores whether Australian mass casualty and disaster plans explicitly acknowledge or implicitly draw upon ethical principles. Methods: Federal, state and territory governmental websites were searched to identify mass casualty incident and/or disaster plans. The authors examined the documents to identify whether ethical principles were overtly stated or implied, and what those values or principles were. Results: Ten governmental documents were identified – two federal and one for each of the eight States and Territories. One of the documents had an explicit statement of the ethical values that informed the mass casualty and disaster planning decisions which were present. Utilitarianism was the dominant ethical principle informing the document in another seven documents. Conclusion: In Australian government documents for mass casualty and disaster management, although ethics is definitely considered, the ethical principles on which decisions are made are rarely explicit. Mass casualty and disaster decision-making could be improved by making the ethical basis for decision-making clear, transparent and comprehensively reasoned.