This article concerns national, sub-national, and historical flags whose reverse is, or was, at some point of their history, different from the obverse.

Nation	Subdivision	Dates	Obverse	Reverse	Notes
Argentina	San Juan
Bulgaria	Stara Zagora
Moldova		1990–2010			Flag of Moldova
Moldova	Transnistria				Flag of Transnistria
Paraguay					Flag of Paraguay
Philippines		1898-1901			Flag of First Philippine Republic Obverse has "Fuerzas Expeditionarias del Norte de Luzon" inscribed Reverse has the words "Libertad Justicia e Igualdad" inscribed.
Sahrawi Arab Democratic Republic
Soviet Union		1923-1991			While the flag was officially two-sided, in practice the flag was usually made through and through. All flags of the constituent republics of the Soviet Union did not bear the hammer and sickle on their reverse side.
Spain	Arapiles
United States	Alabama	1861–1865			Flag of Alabama
	Massachusetts	1908–1971			In 1971 the pine tree design on the reverse of the flag of Massachusetts was replaced by the obverse design; a shield depicting an Algonquian Native American with bow and arrow, with the arrow pointed downwards signifying peace.
	Oregon				The flag of Oregon is currently the only double-sided state flag.

See also[edit]

• Glossary of vexillology
• Vexillology