A false belief your character holds about themselves or the world that shapes their flawed decisions until the story forces them to confront it.
The lie the character believes is a foundational misconception that drives your character's behavior from the start of the story. It's usually born from a painful past experience and feels absolutely true to the character, even though it's holding them back. The entire narrative arc often revolves around the character either overcoming this lie (positive arc), succumbing to it further (negative arc), or proving it wrong to others (flat arc). The concept was popularized by writing teachers like K.M. Weiland and Lisa Cron.
The lie gives your story emotional structure. Without it, character growth feels random or forced. With it, every scene can push against or reinforce the lie, creating a sense of momentum that readers feel even when they can't name it. It's the invisible thread that connects your character's backstory to their climactic choice.
Elizabeth believes she's an excellent judge of character. This lie causes her to misjudge both Darcy and Wickham, nearly costing her everything.
Tony Stark believes that weapons and technology can protect people without personal sacrifice. The story forces him to literally put his body on the line.
Connell believes he's not worthy of being seen or valued in public. This lie drives him to hide his relationship with Marianne and causes years of miscommunication.
Amir believes he's a coward who can never redeem himself. The entire novel is structured around him confronting and ultimately disproving that belief.
Let the lie feel reasonable at first. The reader should understand why the character believes it, even if they suspect it's wrong.
Show the lie through behavior and decisions. Let the reader piece it together rather than being told directly.
The character needs a scene where the lie is tested to its breaking point. Growth without pain doesn't feel earned.
Write a scene where your character makes a decision that feels completely logical to them but is clearly misguided to the reader. After the scene, write one sentence naming the lie behind that decision. Then write a second brief scene set later in the story where the same lie is tested - but this time, the character hesitates.