Ukraine:
18 years of age; universal
United Arab Emirates:
none
United Kingdom:
18 years of age; universal
United States:
18 years of age; universal
Uruguay:
18 years of age; universal and compulsory
Uzbekistan:
18 years of age; universal
Vanuatu:
18 years of age; universal
Venezuela:
18 years of age; universal
Vietnam:
18 years of age; universal
Virgin Islands:
18 years of age; universal; note - indigenous
inhabitants are US citizens but do not vote in US presidential
elections