The flag of Rhodesia changed with political developments in the country. At independence in 1965 the recently adopted flag of Southern Rhodesia was used, until a new flag was adopted in 1968. The 1968 flag remained in use following the declaration of the republic in 1970 and it was also initially the flag of Zimbabwe Rhodesia until a new flag was adopted in September 1979.

Rhodesia's Unilateral Declaration of Independence (UDI) was a statement adopted by the Cabinet of Rhodesia on 11 November 1965, announcing that Rhodesia a British territory in southern Africa that had governed itself since 1923, now regarded itself as an independent sovereign state. The culmination of a protracted dispute between the British and Rhodesian governments regarding the terms under which the latter could become fully independent, it was the first unilateral break from the United Kingdom by one of its colonies since the United States Declaration of Independence in 1776. The UK, the Commonwealth, and the United Nations all deemed Rhodesia's UDI illegal, and economic sanctions, the first in the UN's history, were imposed on the breakaway colony. Amid near-complete international isolation, Rhodesia continued as an unrecognised state with the assistance of South Africa and Portugal.