Charles Magniac (1827 – 23 November 1891) was a British financier and Liberal politician who sat in the House of Commons in two periods between 1868 and 1886.
Magniac was the eldest son of Hollingworth Magniac of Colworth, Bedfordshire. Following education at Eton College and the University of Cambridge, he worked in finance in the City of London, becoming a partner in Matheson and Company of Lombard Street. He was appointed a deputy lieutenant for the City, and was the first president of the London Chamber of Commerce. In about 1869 Magniac purchased Chesterfield House the great Mayfair townhouse built 1747-52 by Philip Stanhope, 4th Earl of Chesterfield, which had been threatened with demolition.
Magniac was a committed Liberal, and was elected as a member of parliament for the party on a number of occasions. He was first elected as an MP in 1868, representing St Ives, Cornwall. A contemporary political reporter commented:
"St Ives, (Cornwall) scared away Mr Paull (C), and embraced Mr. Magniac (L), of the firm of Matheson & Co., the frightfully rich China merchants in the City, who when they lose a quarter of a million [pounds] are no more concerned about it than I should be if I were to lose half a crown."