This overview lists flags used by first-level and second-level country subdivisions. The flags of country subdivisions exhibit a wide variety of regional influences and local histories, as well as widely different styles and design principles. For example, some Indonesian provincial flags features a coat of arms, due to many provincial coat of arms within the province used on their flag. Some Estonian county flags features the green and white background with the coat of arms of the county. Subdivision flags were not always ubiquitous. Many country subdivisions went decades without a flag, until a certain event or an independence or a formation of the country to adopt a creation of the flag. A panel then reviewed the five winning entries, choosing one to become the official subdivision flag. Western Australia's example is typical of the flag adoption processes that many subdivisions undertook with their flags. The 1,000th anniversary of Gloucestershire's founding also spurred the creation of a flag, in 2008. The status of these flags varies from one country or sovereign state to the next: most of them are official flags, whereas others are only used de facto, sometimes to indicate a desire for more autonomy or independence. Some flags, such as the flags of Leicestershire and Warwickshire, were created by the College of Arms in the United Kingdom.

Due to its size, the list is split into continents:

• List of country subdivision flags in Africa
• List of country subdivision flags in Europe
• List of country subdivision flags in North America

This list is incomplete; you can help by adding missing items. (August 2008)

Some Armenian provinces are known to have no flag, including Aragatsotn, Ararat, Armavir, Gegharkunik, and Kotayk Provinces.

Many Indonesian provincial flags feature their coat of arms on a flag, incorporating elements from the coat of arms, itself based on the flags of the regencies and cities, into their designs.

Each department in Uruguay has its own flag (with the exception of Tacuarembo Department).

Wikimedia Commons has media related to Flags of country subdivisions.

• Flags of country subdivisions (Oceania)
• Gallery of sovereign state flags
• Flags of dependent territories
• Gallery of flags of dependent territories
• History of flags
• Flags of formerly independent states
• Cultural flags
• Flags of ethnic groups
• Lists of city flags
• Flags of micronations