What Is Not Yours Is Not Yours is a collection of nine short stories by British writer Helen Oyeyemi. Many of the stories are linked, not just thematically, but also by the use of recurring characters.

"Books and Roses" is about Montserrat and Señora Lucy, who are joined by their mysterious pasts and the keys they both wear around their necks. "'Sorry' Doesn't Sweeten Her Tea" examines the link between fame, violence, and privilege, as two sisters, Aisha and Day, react to news of their favorite singer sexually assaulting a woman—and their stepfather, Anton, reacts to them.

Day is also a character in "A Brief History of the Homely Wench Society," all about a Cambridge University club formed in response to a men-only student group. Similarly, Aisha also pops up in "Freddy Barrandov Checks … In?" which tells the story of a young man struggling to retain his independence as he's pushed toward working at the same hotel where his parents work.

The workplace is also central to "If a Book Is Locked There's Probably a Good Reason For That Don't You Think," which probes office politics and social interactions, as everyone is infatuated with the organization's newest hire, Eva…until they're not anymore. Then Eva becomes the focus of their bullying.

In addition to connected characters, themes, and settings, the stories in What is Not Yours Is Not Yours are also linked by magical, dream-like elements. "Drownings," for example, is about a tyrant who, as the title suggests, drowns people. On his wedding day, he tries to set his bride on fire, only to find that she's fire-resistant. When she tries to set him ablaze with a fiery hug, he flees for the water, only to be thwarted by the ghosts of all the people he drowned. "Presence" centers on a pair of married psychologists with abandonment issues who hallucinate that they have a pre-teen son. "Is Your Blood As Red As This?" is about the relationships between puppeteering students, and features a ghost and a anthropomorphized wooden devil amongst its cast of characters, the latter of which calls Pinocchio to mind. "Dornicka and the St. Martin's Day Goose," meanwhile, is a twisted retelling of the Little Red Riding Hood story.