Lord Ruthven is a fictional character. He was one of the first vampires in English literature.

There is a genuine title of Lord Ruthven of Freeland which is a subsidiary title of the Earl of Carlisle in the United Kingdom. The fictional characters are not related to the historical title holders.

The first fictional Lord Ruthven appeared in the 1816 novel Glenarvon by Lady Caroline Lamb. This character was based on the genuine Lord Byron and was not a vampire. Lady Caroline was a former lover of Lord Byron's and the novel did not offer a flattering portrait.

Lord Ruthven appeared as the titular character in the 1819 novel The Vampyre. The short novel had been written in 1816 by Dr. John William Polidori another acquaintance of Byron's. It was published in the April 1819 edition of the New Monthly Magazine. The publishers falsely attributed the authorship to Byron. Both Byron and Polidori disputed this attribution.

In the novel, a young Englishman Aubrey meets Lord Ruthven, a man of mysterious origins who has entered London society. Aubrey accompanies Ruthven to Rome but leaves him after Ruthven seduces the daughter of a mutual acquaintance. Aubrey travels to Greece where he becomes attracted to Ianthe, an innkeeper's daughter. Ianthe tells Aubrey about the legends of the vampire. Ruthven arrives at the scene and shortly thereafter Ianthe is killed by a vampire. Aubrey does not connect Ruthven with the murder and rejoins him in his travels. The pair are attacked by bandits and Ruthven is mortally wounded. Before he dies, Ruthven makes Aubrey swear an oath that he will not mention his death or anything else he knows about Ruthven for a year and a day. Looking back, Aubrey realizes that everyone who Ruthven met ended up suffering.

Aubrey returns to London and is amazed when Ruthven appears shortly thereafter, once again alive. Ruthven reminds Aubrey of his oath to keep his death a secret. Ruthven then begins to seduce Aubrey's sister while Aubrey, helpless to protect his sister, has a nervous breakdown. Ruthven and Aubrey's sister are engaged to marry on the day the oath ends. Aubrey writes a letter to his sister revealing Ruthven's history and dies. The letter does not arrive in time. Ruthven marries Aubrey's sister, kills her on their wedding night, and escapes.

The novel was an immediate success and several other authors quickly adapted the character of Lord Ruthven into other works. Cyprien Bérard wrote an 1820 novel, Lord Ruthwen ou les Vampires which was falsely attributed to Charles Nodier. Nodier himself wrote an 1820 play, Le Vampire which was adapted back into English for the London stage by James Robinson Planché as The Vampire, or The Bride of the Isles. At least four other stage versions of the story also appeared in 1820. In 1828, Heinrich August Marschner and W.A. Wohlbruck adopted the story into a German opera, Der Vampyr. A second German opera, using the same name, also was written in 1828 by Peter Josef von Lindpainter and Casar Max Heigel . Dion Boucicault revived the character in his 1852 play The Vampire: A Phantasm and played the title role during its long run. Alexandre Dumas also used the character in an 1852 play.

After the appearance of Dracula in 1897, Ruthven's fame faded. However the character has still been used as the inspiration for a 1945 film, The Vampire's Ghost and was adapted into comic book format in 1973. Lord Ruthven is used as a character in the background of the Vampire: The Masquerade game system. Kim Newman uses the character of Lord Ruthven in his Anno Dracula series, having Ruthven serve as Prime Minister after Dracula seizes the English throne.