My Son, My Son, What Have Ye Done is a 2009 crime drama film directed by Werner Herzog, and written by Herzog and Herbert Golder. The film stars Michael Shannon as Brad McCullam, a mentally unstable man who kills his own mother (played by Grace Zabriskie) after becoming obsessed with a play he is starring in. The film follows a hostage situation resulting from the murder, while also showing the events of McCullam's life leading up to the murder in flashback, with Willem Dafoe appearing as the lead detective, and Chloë Sevigny as McCullam's fiancée.

The film is loosely based on the story of Mark Yavorsky, an actor at the University of San Diego who reenacted a scene from Orestes by murdering his mother with an antique saber. However, Herzog has stated that "about 70 percent of the script is false", with Herzog and Golder desiring to deviate from the true events, and instead focus on the main character's mental state. The film was conceived and written in 1995, but Herzog and Golder were unable to find anyone to produce it. David Lynch eventually became interested, and produced the film through his production company Absurda.

The film premiered at the 2009 Venice Film Festival on September 5, 2009, where it was nominated for the Golden Lion, along with another film directed by Herzog, Bad Lieutenant: Port of Call New Orleans. This marked the first time that two films in one year by the same director were nominated for the award.