- The novel's protagonist. After her ex-boyfriend, Pierce Inverarity, names her executor of his immense and complex estate, she discovers and begins to unravel a worldwide conspiracy in southern California. Oedipa functions in the novel as a type of detective, although the story is as much about her own self-discoveries as it is about the mystery she attempts to piece together.
- The husband of Oedipa, Mucho once worked in a used-car lot but recently became a disc jockey for KCUF radio in Kinneret. At the end of the novel, he goes crazy on LSD, alienating Oedipa.
- Oedipa's ex-boyfriend and a fabulously rich real-estate tycoon. We never meet him except in Oedipa's memories, which tell us that he liked to play with his own voice by doing vocal impersonations. He was a general jokester in real life and may be playing a mean trick on Oedipa by inventing this whole Tristero conspiracy.
- A lawyer who works for Warpe, Wistfull, Kubitschek and McMingus. He has been assigned to help Oedipa execute Pierce's estate. He and Oedipa have a brief affair in San Narciso as they go about untangling the mystery. He disappears around the middle of the novel.
Miles, Dean, Serge and Leonard
- The four members of the hippie band called The Paranoids. They serve as a means of satirizing the southern Californian youth hippie culture in the mid-60s.
- A member of the Peter Pinguid Society, a right-wing anti-government organization. Oedipa and Metzger meet him in a bar called The Scope early in chapter three; he appears sporadically through the rest of the novel.
Manny di Presso
- A lawyer and old friend of Metzger, he resides near Lake Inverarity. One of his client's is suing Inverarity's estate for money Inverarity owed. The client sent Inverarity human bones recovered from an Italian lake for use in charcoal production.
- The director of the production of The Courier's Tragedy
seen by Oedipa and Metzger in chapter three. Driblette is a leading Wharfinger scholar, but he commits suicide toward the end of the novel before Oedipa can extract any useful information from him about Wharfinger's mention of the Tristero.
- The president of Yoyodyne. Oedipa meets him in Chapter Four as he hosts a sing-along at a stockholders meeting.
- Oedipa's psychiatrist, he goes insane and admits to having been a Nazi doctor at Buchenwald and to liking to make a particularly incredible facial expression that drives people to devastation.
- An employee of Yoyodyne, Oedipa meets him when she wanders into his office while touring the plant. He knows something about the Tristero but will not reveal to her what he knows.
- A scientist obsessed with perpetual motion. He has tried to invent a type of Maxwell's Demon. Oedipa visits him to see the machine after learning about him from Stanley Koteks. He shows her the machine but causes her to run away when he propositions her.
- A stamp expert whom Oedipa hires to go through Pierce's extensive stamp collection in order to appraise it. Genghis provides some more clues to help Oedipa solve the Tristero mystery.
- An English professor who used to teach at UC-Berkeley but later moved to San Narciso College. He helps Oedipa untangle some of the mysteries related to the Wharfinger play's mention of Tristero.