Charles Boit (, 10 August 1662 — Paris, 6 February 1727) was a Swedish painter in vitreous enamels who mostly worked in England, Austria and France.
Boit was born in a Huguenot family in Stockholm, the son of a merchant who was also master of the royal indoor tennis court. He became a goldsmith's apprentice at the age of fifteen. After qualifying as a journeyman in 1682, he went to Paris for three months before returning to Sweden, settling in Gothenburg and getting married. According to Swedish art historian Gunnar W. Lundberg, he probably studied in Sweden with Pierre Signac, who had come from France in the mid-17th century and served as court enameller to Queen Christina.
He first travelled to England in 1687. Lack of means forced Boit to take a position as a drawing master for children in the country; according to a story retold in the Anecdotes of Painting in England of Horace Walpole, based on the notes of George Vertue, he "engaged one of the scholars, a gentleman's daughter, to marry him, but the affair being discovered, Boit was thrown into prison". According to the Anecdotes, Boit remained in confinement for two years. Once free, he was able to establish himself as an enameller in London, aided by his countryman, the popular Swedish-born portrait painter Michael Dahl, to whom he probably owed a large part of his immediate and considerable success as a painter of miniature portraits. Boit was appointed court enameller to William III in March 1696.
In 1699 Boit left England for Holland and Düsseldorf, where he produced work for the family of the Elector Palatine, and continued to Vienna. He painted a very large enamel portrait of Emperor Leopold and his family (1703) for which he is said to have received 6,000 ducats or 20,000 florins. The painting, 38 x 46 cm in size and now in the Kunsthistorisches Museum (Vienna), is said to have cracked after one of the Imperial princes sat down on it.