Mrs Charlotte Melmoth (c. 1749 – 1823) was an 18th-century English actress, the estranged spouse of British actor/writer Samuel Jackson Pratt ("Courtney Melmoth"), and known as "The Grande Dame of Tragedy on the Early American Stage". After a moderately successful stage career in Great Britain and Ireland, she emigrated to the United States of America in 1793 and became one of the best-known actresses of the late 18th/early 19th century.

Little is known of Charlotte Melmoth's early years; she may have been an English farmer's daughter. Her birth name is uncertain. She first came to the attention of the British public in the late 18th century, as "Mrs Courtney Melmoth" part of an acting duo with her common-law husband, clergyman-turned actor Samuel Jackson Pratt. It is not known whether she adopted her husband's stage-surname "Melmoth" or, as has been speculated, "Melmoth" was her real surname and Pratt adopted it as his own stage name.

Most biographers give her year of birth as 1749, the same as Pratt's. However this would put her in her twenties in the early 1770s, when she first met Pratt, in contradiction of another biographer's claim that she was still at school when this meeting occurred. According to A History of The City of Brooklyn, Melmoth "had been duped into a sham marriage, while at boarding school, by a Mr. Pratt (known in the literary and theatrical circles of that day as Courtney Melmoth), and with him went upon the stage, playing in several companies both in England and Ireland." Pratt's parents strongly disapproved of the relationship and it is not known whether the marriage was legally formalised. The couple toured together in theatrical productions, not always successfully, and sometimes had to resort to telling fortunes to make their living. In 1773 the couple opened a theatre in Drogheda, County Louth, Ireland. The venture was not successful and the theatre failed within three months, whereupon the couple moved to London, where Melmoth began to achieve success as an actress, both at Covent Garden and Drury Lane. From 1776 to 1779 the couple played seasons in Edinburgh, London and Birmimgham.

From 1777 to 1778, the couple were in Paris, where they made the acquaintance of Benjamin Franklin. The couple were present in January 1778 when Franklin gave a copy of his portrait to a certain Mrs Izard, but neglected to give a similar copy to Melmoth. The incident inspired Melmoth to write a poem, "Impromptu, To Doctor Franklin For the Author who was present when he gave his Portrait to a Lady", which Pratt sent to Franklin. Franklin replied, apologising for not realising that Melmoth also wanted a copy of the portrait.

The couple were by now experiencing serious financial problems — Pratt had already borrowed money from a friend, Mrs Montagu, and attempted to borrow money from Samuel Johnson) — and, on 29 January 1778, the day after receiving Franklin's response to Melmoth's poem, Pratt wrote to Franklin asking to borrow money from him, to which Franklin agreed. He then asked for a further loan four days later and, on 3 March begged Franklin for "a small allowance by week or month, in order to assist my slender Circumstances". A further request for money was made on 12 May, shortly before the "Melmoths" returned to England, to which Franklin replied that he found the requests for money "a greater inconvenience to myself than you perhaps imagined", but agreeing to the further loan, relying "on your Honour and Punctuality for the speedy Repayment". On 22 June 1778 Pratt wrote to Franklin from London regretting that he and Melmoth were unable to repay the money, whereupon the friendship with Franklin appears to have abruptly ended. By 1781 Pratt and Melmoth had separated, and Melmoth, retaining her professional surname, continued her acting career in Ireland. In 1793 she emigrated to the United States.

Melmoth made her stage debut in May 1773 at The Smock Alley Theatre, Dublin, playing Monimia in The Orphan. In late 1773 Melmoth and Pratt opened their own theatre in Drogheda, with a production of The Merchant of Venice, in which Melmoth played Portia to Pratt's Shylock, but the theatre failed and, after three months, the couple moved to London.

In February 1774 she debuted at Covent Garden as Calista in The Fair Penitent. Westminster Magazine reviewed her performance with the words, "Her figure is pleasing and also she is young and handsome ... she possesses the internal as well as external requisites of a good actress; for she discovers great feeling and sensibility; and indeed promises to be a great ornament to the theatre". Later that year, also at Covent Garden, she played Roxana in Nathaniel Lee's The Rival Queens or The Death of Alexander The Great, a role she would reprise at other times in her career. Amongst other roles she played at Covent Garden that season are Eleanor in Henry II, Hermione in A Winter's Tale and Queen Elizabeth in Henry Jones' tragedy, The Earl of Essex. In 1776 she played Edinburgh with her husband, where, among many other leading roles, she played Alicia in The Tragedy of Jane Shore, Viola in Twelfth Night and Mrs Belville in School for Wives. In Edinburgh she also played Lady Macbeth for the first time – a role for which she would eventually become famous.

In November 1776 she made her debut at Drury Lane as Lady Macbeth and the following February, reprised her role as Roxanne in The Rival Queens, alongside Mary Robinson. This would be her last appearance in London; the following year she and her husband were in Paris, then in 1778 and 1779 they played two seasons in Edinburgh, where Melmoth began to add Comic parts (including Lady Sneerwell in The School for Scandal) to her previously tragic repertoire. In late 1779, after a season in Birmingham, Melmoth's success seems to have faded for a while, and the couple travelled Britain seeking work, occasionally telling fortunes for a living.