Charles, Prince of Wales (born 1948), heir-apparent to the thrones of the Commonwealth Realms, may assume the name "Charles III" if, and when, he succeeds Elizabeth II, although he has also suggested that he may choose the regnal name "George VII", believing that the regnal name Charles is jinxed.

Carl III Johan of Norway and XIV of Sweden (1763–1844).

Charles III, Holy Roman Emperor, "the Fat" (832–888).

Charles the 3rd is a boss character from the video game Viewtiful Joe.

Charles Edward Stuart (1720–1788), the Young Pretender, styled himself "Charles III, King of England and Scotland".

Charles III of Spain (1716–1788).

Charles III, Prince of Monaco (1818–1889).

Charles III of Hungary, also Charles VI, Holy Roman Emperor (1685–1740).

Charles III, Duke of Parma (1823–1854).

Charles III, Duke of Bourbon (1490–1527).

Charles III of Naples (died 1386).

Charles III, Duke of Savoy, "the Good" (1486–1553).

Charles III of France, "the Simple" (879–929).

Karl III Philip, Elector Palatine (1661–1742).

Charles III, Duke of Lorraine (1543-1608).

Charles III of Navarre, "the Noble" (1361–1425).

Charles III of Alençon (1337–1375).