| Country | Flag description |
| Turks and Caicos Islands | blue, with the flag of the UK in the upper hoist-side quadrant and the colonial shield centered on the outer half of the flag; the shield is yellow and contains a conch shell, lobster, and cactus |
| Tuvalu | light blue with the flag of the UK in the upper hoist-side quadrant; the outer half of the flag represents a map of the country with nine yellow five-pointed stars symbolizing the nine islands |
| Uganda | six equal horizontal bands of black (top), yellow, red, black, yellow, and red; a white disk is superimposed at the center and depicts a red-crested crane (the national symbol) facing the hoist side |
| Ukraine | two equal horizontal bands of azure (top) and golden yellow represent grain fields under a blue sky |
| United Arab Emirates | three equal horizontal bands of green (top), white, and black with a wider vertical red band on the hoist side |
| United Kingdom | blue field with the red cross of Saint George (patron saint of England) edged in white superimposed on the diagonal red cross of Saint Patrick (patron saint of Ireland), which is superimposed on the diagonal white cross of Saint Andrew (patron saint of Scotland); properly known as the Union Flag, but commonly called the Union Jack; the design and colors (especially the Blue Ensign) have been the basis for a number of other flags including other Commonwealth countries and their constituent states or provinces, and British overseas territories |
| United States | 13 equal horizontal stripes of red (top and bottom) alternating with white; there is a blue rectangle in the upper hoist-side corner bearing 50 small, white, five-pointed stars arranged in nine offset horizontal rows of six stars (top and bottom) alternating with rows of five stars; the 50 stars represent the 50 states, the 13 stripes represent the 13 original colonies; known as Old Glory; the design and colors have been the basis for a number of other flags, including Chile, Liberia, Malaysia, and Puerto Rico |
| United States Pacific Island Wildlife Refuges | the flag of the US is used |
| Uruguay | nine equal horizontal stripes of white (top and bottom) alternating with blue; a white square in the upper hoist-side corner with a yellow sun bearing a human face known as the Sun of May with 16 rays that alternate between triangular and wavy |
| Uzbekistan | three equal horizontal bands of blue (top), white, and green separated by red fimbriations with a white crescent moon and 12 white stars in the upper hoist-side quadrant |
| Vanuatu | two equal horizontal bands of red (top) and green with a black isosceles triangle (based on the hoist side) all separated by a black-edged yellow stripe in the shape of a horizontal Y (the two points of the Y face the hoist side and enclose the triangle); centered in the triangle is a boar's tusk encircling two crossed namele leaves, all in yellow |
| Venezuela | three equal horizontal bands of yellow (top), blue, and red with the coat of arms on the hoist side of the yellow band and an arc of eight white five-pointed stars centered in the blue band |
| Vietnam | red field with a large yellow five-pointed star in the center |
| Virgin Islands | white field with a modified US coat of arms in the center between the large blue initials V and I; the coat of arms shows a yellow eagle holding an olive branch in one talon and three arrows in the other with a superimposed shield of vertical red and white stripes below a blue panel |
| Wake Island | the flag of the US is used |
| Wallis and Futuna | unofficial, local flag has a red field with four white isosceles triangles in the middle, representing the three native kings of the islands and the French administrator; the apexes of the triangles are oriented inward and at right angles to each other; the flag of France, outlined in white on two sides, is in the upper hoist quadrant; the flag of France is the only official flag |
| West Bank | void |
| Western Sahara | void |
| World | void |
| Yemen | three equal horizontal bands of red (top), white, and black; similar to the flag of Syria, which has two green stars in the white band, and of Iraq, which has an Arabic inscription centered in the white band; also similar to the flag of Egypt, which has a heraldic eagle centered in the white band |
| Zambia | green field with a panel of three vertical bands of red (hoist side), black, and orange below a soaring orange eagle, on the outer edge of the flag |
| Zimbabwe | seven equal horizontal bands of green, yellow, red, black, red, yellow, and green with a white isosceles triangle edged in black with its base on the hoist side; a yellow Zimbabwe bird representing the long history of the country is superimposed on a red five-pointed star in the center of the triangle, which symbolizes peace; green symbolizes agriculture, yellow - mineral wealth, red - blood shed to achieve independence, and black stands for the native people |