Victor Frankenstein, whose character name has sometimes evolved in popular culture to Dr. Frankenstein, is a fictional character who first appeared as the titular main protagonist of Mary Shelley's 1818 novel Frankenstein; or, The Modern Prometheus. He is a young Italian-born Swiss scientist who, after studying chemical processes and the decay of living things at university, gains an insight into the creation of life and gives life to his own creature (often referred to as Frankenstein's monster, or often colloquially referred to as simply "Frankenstein"). Victor later regrets meddling with nature through his creation, as he inadvertently endangers his own life and the lives of his family and friends when the creature seeks revenge against him. He is first introduced in the novel when he is seeking to catch the monster near the North Pole and is saved from potential fatality by Robert Walton and his crew.

Some aspects of the character are believed to have been inspired by 17th-century alchemist Johann Konrad Dippel. Certainly, the author and people in her environment were aware of the experiment on electricity and dead tissues by Luigi Galvani and his nephew Giovanni Aldini and the work of Alessandro Volta at the University of Pavia.

Percy Shelley, Mary's husband, served as a significant influence for the character. Victor was a pen name of Percy Shelley's, as in the 1810 collection of poetry he wrote with his sister Elizabeth, Original Poetry by Victor and Cazire. There is speculation that Percy was one of Mary Shelley's models for Victor Frankenstein; while a student at Eton College, he had "experimented with electricity and magnetism as well as with gunpowder and numerous chemical reactions", and his rooms at the University of Oxford were filled with scientific equipment. Percy Shelley was the first-born son of a wealthy, politically connected country squire, and a descendant of Sir Bysshe Shelley, 1st Baronet of Castle Goring, and Richard Fitzalan, 10th Earl of Arundel. As stated in the novel, Frankenstein's family is one of the most distinguished of the Genevese republic and his ancestors were counselors and syndics. Percy Shelley's sister and Frankenstein's adopted sister were both named Elizabeth. On 22 February 1815, Mary Shelley delivered a baby two months premature; the child died two weeks later. The question of Frankenstein's responsibility to the creature – in some ways like that of a parent to a child – is one of the main themes of the book.

One of the characters of François-Félix Nogaret [fr]'s 1790 novella Le Miroir des événements actuels ou la Belle au plus offrant is an inventor named "Wak-wik-vauk-an-son-frankésteïn", then abridged as "Frankésteïn", but there is no proof Shelley had read it.

Victor Frankenstein was born in Naples (according to the 1831 edition of Shelley's novel) to a Swiss family from Geneva. He was the son of Alphonse Frankenstein and Caroline Beaufort, who died of scarlet fever when Victor was 17. He describes his ancestry thus: "I am by birth a Genevese; and my family is one of the most distinguished of that republic. My ancestors had been for many years counsellors and syndics; and my father had filled several public situations with honour and reputation." Frankenstein has two younger brothers – William, the youngest, and Ernest, the middle child. Frankenstein falls in love with Elizabeth Lavenza, who became his adoptive sister (his blood cousin in the 1818 edition) and, eventually, his fiancée.

As a boy, Frankenstein is interested in the works of alchemists such as Cornelius Agrippa, Paracelsus, and Albertus Magnus, and he longs to discover the fabled elixir of life. At the age of fifteen, he loses interest in both these pursuits and in science as a whole after he sees a tree destroyed by a lightning strike and a scientist explains the theory of electricity to him. It seems to him as if nothing can really be known about the world, and he instead devotes himself to studying mathematics, which he describes as "being built upon secure foundations." However, at the University of Ingolstadt in Bavaria, Frankenstein develops a fondness for chemistry, and within two years, his commitment and scientific ability allow him to make discoveries that earn him admiration at the university. He then becomes curious about the nature of life and his studies lead him to a miraculous discovery that enables him to create life in inanimate matter.

Assembling a humanoid creature from parts of corpses and ambiguous means involving electricity, Frankenstein successfully brings it to life, but he is horrified by the creature's ugliness. He flees from his creation, who disappears and, after several negative encounters with the locals, swears revenge on his creator. When his youngest brother, William, is found murdered, Frankenstein knows instantly that his creation is the killer, but says nothing. The Frankensteins' housekeeper, Justine, is blamed for the boy's death and executed; Frankenstein is wracked with guilt but does not come forward with the truth because he thinks no one will believe his story, and he is afraid of the reactions such a story would provoke.

The creature approaches Frankenstein and begs him to create a female companion for him. Frankenstein agrees, but ultimately destroys this creation, fearing the idea of a whole race of monsters being born. Enraged, the creature swears revenge; he kills Henry Clerval, Frankenstein's best friend, and promises Frankenstein, "I shall be with you on your wedding night." The creature keeps his promise by strangling Elizabeth on her matrimonial bed. Within a few days, Frankenstein's father dies of grief. With nothing else left to live for, Frankenstein dedicates his life to destroying the creature.