Charles of Austria, nicknamed the Posthumous, (Graz, August 7 1590 - Madrid, December 28 1624) was Bishop of Wrocław and grandmaster of the Teutonic Knights.

He was the youngest son of Charles II, Archduke of Austria and Maria Anna of Bavaria (1551–1608).

As the youngest of 15 children, he was destined for a career in the Church.
In 1608 he was appointed Bishop of Breslau (Wrocław). In 1613 he became Bishop of Brixen and in 1619 grandmaster of the Teutonic Knights.
Charles was a staunch Catholic. In 1609, he strongly protested against the decision of Rudolf II, Holy Roman Emperor to treat all religions equally in Silesia. After the Battle of White Mountain he forcefully reintroduced Catholicism in the Nysa Region. He founded in 1622 a Jesuit college there.

In 1624 he travelled to Madrid to become Viceroy of Portugal, at the request of King Philip IV of Spain, but he fell ill and died before taking up his post.