Tell No One (French: Ne le dis à personne) is a 2006 French Thriller film directed by Guillaume Canet and based on the novel by Harlan Coben.

Alex Beck (François Cluzet) is a doctor who has slowly been putting his life back together after his wife Margot was murdered by a serial killer. Eight years on, Alex is doing well enough until he finds himself implicated in the murder of two people, with plenty of evidence pointing to him as the killer even though he knows nothing of the crimes. The same day, Alex receives an e-mail that appears to be from Margot (Marie-Josée Croze), which includes a link to a video clip that seems to be recent and features his late wife looking alive and well. Margot's message warns Alex that they are both being watched, and he struggles to stay one step ahead of the law as a gang of strong-arm men intimidate Alex's friends into telling whatever they might know about him. Alex's sister Anne (Marina Hands) persuades her well-to-do lover Helene (Kristin Scott Thomas) to hire a well respected attorney, Elisabeth Feldman (Nathalie Baye), to handle Alex's case. While Elisabeth tries to keep Alex out of jail, she learns that her client has a warrant out for his arrest, and Alex goes on the lam while he and his lawyer struggle to find out the truth about the murder as well as Margot's reappearance.

Tell No One was extremely well received both critically and financially.

As of July 8th, Tell No One has been given an average score of 92% on Rotten Tomatoes.

It took $17 million in its first four weeks at the French box office.