(Mary Sophia) Charlotte Howe, Viscountess Howe (23 September 1703 – 13 June 1782) was a British courtier and politician.
Born Baroness Sophia Charlotte Mary (the order of her baptismal names were later changed after her marriage) von Kielmansegg (probably in Hanover), she was the eldest daughter of the Baron and Baroness von Kielmansegg (later Countess of Leinster and Darlington), the half-sister of George Louis, Elector of Hanover. When the elector became King of Great Britain in 1714, her family followed him to London.
On 8 August 1719, Charlotte married Emanuel Howe, 2nd Viscount Howe. Lord Howe's uncle, Emanuel Scrope Howe, had been the English Minister to Hanover in 1706–9, and the husband of Prince Rupert of the Rhine's illegitimate daughter Ruperta. The Howes were thus already known to the Hanoverian nobility. Lady Howe's close relations with the Royal Family encouraged gossip in Britain that her mother was a mistress of the king and that she was his daughter, but has since been rejected by modern historians. Lady Howe brought a dowry of £5000 and an annuity of £1500 per year. In addition, the king gave the couple £750 per annum, which was later raised to £1250. This helped relieve pressure on the Howe estate at Langar, Nottinghamshire and supported the family's attempts to extend their political patronage. The couple had ten children, among whom were Hon. George Augustus Howe, Hon. Richard Howe and Hon. William Howe (successively Viscounts Howe).