The Danish philosopher Søren Kierkegaard opens his book Philosophical Fragments with the quote "Better well hanged than ill wed" which is a paraphrase of Feste's comment to Maria in Act 1, Scene 5: "Many a good hanging prevents a bad marriage". Nietzsche also refers passingly to Twelfth Night (specifically, to Sir Andrew Aguecheek's suspicion, expressed in Act 1, Scene 3, that his excessive intake of beef is having an inverse effect on his wit) in the third essay of his Genealogy of Morality.
The Kiddy Grade characters Viola and Cesario are named for Viola and her alter ego Cesario, respectively.
Elizabeth Hand's novella Illyria features a high school production of Twelfth Night, containing many references to the play, especially Feste's song.
One of Club Penguin's plays, Twelfth Fish, is a spoof of Shakespeare's works. It is a story about a countess, a jester, and a bard who catch a fish that talks. As the play ends, they begin discussing eating the fish. Many of the lines are parodies of Shakespeare.
Agatha Christie's 1940 mystery novel Sad Cypress draws its title from a song in Act II, Scene IV of Twelfth Night.
American Playwright Ken Ludwig wrote a play inspired by the details of Twelfth Night; called Leading Ladies.
Cassandra Clare's 2009 novel City of Glass contains chapter names inspired by quotations of Antonio and Sebastian.
Two of the dogs in the film Hotel for Dogs are twins called Sebastian and Viola.
Clive Barker's short story "Sex, Death and Starshine" revolves around a doomed production of Twelfth Night.