Prince William Charles Christian of Saxe-Gotha-Altenburg (German: Wilhelm Carl Christian von Sachsen-Gotha-Altenburg; 12 March 1701, Gotha – 31 May 1771, Tonna) was a German prince of the Saxe-Gotha-Altenburg house, a junior line of the Ernestine Wettins.

He was the second surviving son of Frederick II, Duke of Saxe-Gotha-Altenburg (1676–1732) and his wife Magdalena Augusta (1679–1740), daughter of Charles, Prince of Anhalt-Zerbst.

In 1734 he became Generalwachtmeister in the forces of Charles VI, Holy Roman Emperor, commanding the same two regiments that his elder brother Frederick III, Duke of Saxe-Gotha-Altenburg had led against the French.

He made two failed petitions to rise to Reichsgeneralfeldmarschall in 1753 and 1760 and soon afterwards resigned as a Generalfeldzeugmeister to take up residence in Tonna.

In Hamburg on 8 November 1742 he married Anna (1709–1758), daughter of Christian August of Holstein-Gottorp, Prince of Eutin and aunt of Catherine II of Russia.