Victor Frankenstein – The oldest son in the Frankenstein family, the eventual husband of Elizabeth Lavenza, and the novel's protagonist and narrator of most of the story (he tells his story to Robert Walton, who relates it to the reader). From childhood, Victor has a thirst for knowledge and powerful ambition. These two traits lead him to study biology at university in Ingolstadt, where he eventually discovers the "secret of life" and then uses that knowledge to create his own living being. But Frankenstein is also prejudiced, and cannot stand his creation's ugliness. He thinks it a monster though in fact it's kind and loving. Victor's abandonment of his "monster" creates a cycle of guilt, anger, and destruction, in which first the monster takes vengeance upon Victor, and then Victor swears vengeance on the monster. In the end, Victor resembles the monster he hates far more than he would care to imagine.
The Monster – The hideous-looking creature that Victor Frankenstein creates (though the name "Frankenstein" has become associated with the monster, the monster is, in fact, nameless). Though the monster is originally kind and sensitive and wants nothing more than to be loved and accepted, it is surrounded by people who judge it as evil because of its terrible appearance. The monster is isolated and demonized by human society, and soon becomes embittered and enraged at his treatment. Eventually, the monster becomes a killer, not from a criminal thirst to hurt, but from a desire for revenge against Victor and all of humanity for rejecting him.
Robert Walton – An explorer who rescues Victor from the ice, hears his harrowing story, and sets it down on paper in letters to his sister, Margaret Saville. Walton's quest for knowledge in the North Pole parallels Victor's search for education and enlightenment at Ingolstadt. Because he parallels Victor in this way, Robert Walton is a "double" of Victor, whose actions, by mirroring or contrasting Victor's own, serve to highlight Victor's character and various themes in Frankenstein.
Elizabeth Lavenza – Victor's sister by adoption, and later his wife. Elizabeth is a stunningly beautiful and remarkably pure girl whom Victor's mother adopts. All the Frankensteins adore Elizabeth, and Victor, about four years her elder, quickly begins to "protect, love, and cherish" her. Eventually Victor and Elizabeth marry. Through all of it, Elizabeth remains gorgeous, pure, and passive. NOTE: In the first edition (1818) of Frankenstein, Elizabeth is Alphonse's niece and, therefore, Victor's cousin. In the revised 1831 edition, the Frankensteins adopt Elizabeth, as described above.
Henry Clerval – Victor's dear friend from childhood. Victor describes Clerval as having a vast imagination, a sensitive heart, and boundless love of nature. Clerval serves as Victor's guiding light throughout Frankenstein, selflessly helping Victor but never prodding him to reveal his secrets. Clerval's optimism also stands in contrast to Victor's gloominess.
Alphonse Frankenstein – Victor's father. A devoted husband and parent, and a well-respected public magistrate. Alphonse is a loving father to Victor, and a man who believes in family and society.
Justine Moritz – A young woman who the Frankensteins adopt at the age of 12. She is convicted of the murder of William Frankenstein on circumstantial evidence and executed. Though all the Frankenstein's believe she is innocent, only Victor knows that the monster is the true murderer.
William Frankenstein – Victor's youngest brother, beloved by everyone. The monster strangles him in a forest near Geneva.
Ernest Frankenstein – Victor's younger brother by six years. He is the only Frankenstein to survive the novel.
Caroline Beaufort – Beaufort's daughter, Victor's mother, and Alphonse Frankenstein's wife. Caroline is an example of idealized womanhood: smart, kind, generous, and resourceful. Caroline dies of scarlet fever when Victor is seventeen.
Beaufort – Caroline's father and a close friend to Alphonse Frankenstein. Beaufort was a merchant who fell into poverty and moved to Lucerne with his daughter. He died soon thereafter.
De Lacey – A blind old man who lives in exile with his children Felix and Agatha in a cottage and a forest. As a blind man, De Lacey can't perceive the monster's wretched appearance and therefore does not recoil in horror at his presence. He represents the goodness of human nature in the absence of prejudice.
Felix – The son of De Lacey and brother of Agatha. Felix falls in love with Safie and marries her in exchange for helping her father escape from prison. When the monster enters his family's cottage in Germany, Felix pelts it with rocks and chases it away.
Agatha – De Lacey's daughter. She represents an ideal of womanliness: kind, gentle, and devoted to her family.
Safie – The young Turkish "Arabian" whose beauty captivates Felix. Though raised as a Muslim, she longs for a freer and happier life with Felix, a Christian.
Margaret Saville – Robert Walton's sister and the recipient of his letters, which frame the novel.
M. Waldman – Victor's chemistry professor at Ingolstadt. He supports Victor's pursuit of "natural philosophy," especially chemistry, and becomes a mentor to Victor.
M. Krempe – Victor's professor of natural philosophy at Ingolstadt. A short squat conceited man, Krempe calls Victor's studies "nonsense."
Mr. Kirwin – An Irish magistrate.