Charles Emmanuel IV (Carlo Emanuele Ferdinando Maria; 24 May 1751 – 6 October 1819) was King of Sardinia and ruler of the Savoyard states from 16 October 1796 until 1802, when he abdicated in favour of his brother Victor Emmanuel I. Carlo Emanuele Ferdinando Maria di Savoia was born in Turin, the eldest son of Victor Amadeus III, King of Sardinia, and of his wife Infanta Maria Antonia Ferdinanda of Spain.

From his birth to his succession to the throne of Sardinia in 1796, Charles Emmanuel was styled "Prince of Piedmont".

He was so moved by her death that he decided to abdicate, on 4 June 1802, in favour of his brother Victor Emmanuel I.

Charles was descended from Henrietta Anne Stuart, the youngest daughter of King Charles I of England, whereas Henry Benedict Stuart was descended from Henrietta Anne's brother James II.

In 1815, at the age of sixty-four, Charles Emmanuel took simple vows in the Society of Jesus (the Jesuits).