The naitional banner o the Principality of Andorrae wis adoptit in 1866. The banner is a vertical tricolour o blue, yellow, an red wi the coat o airms o Andorrae in the centre. Although the three vertical bars mey at first appear tae be o equal width, the centre yellow bar is slichtly wider than the ither twa so that the ratio o bar widths is 8:9:8. The oweraw banner ratio is 7:10.
The design is relatit tae the banners o Fraunce an Spain, the twa states that protect the unthirldom o the sma state. A banner o three bars is similar tae that o the French Tricolore, while the pattern o a wider middle stripe can be notit on the Spaineyie banner. The blue an red o the Andorran banner are an aa foond on the French banner, wi red an yellow an aa being the principal colors o the Spainyie banner. Frae 1806 tae 1866, Andorrae's banner wis a vertical bi-color o yellow an red. The motto in the coat o airms in the middle stripe Virtus Unita Fortior means "Strength Unitit is Stranger".
The design is similar tae the banners o Romanie, Moldovae, Chad an the banner o Queen's University in Ontario, Canadae. Aw o these are vertical tricolours o blue, yellow, an red, but unlike that o Andorrae, their banners aw hae stripes o equal breadth.