"I Have No Mouth and I Must Scream" is a dystopian science fiction short story by Harlan Ellison. The story was first published in the March 1967 issue of IF: Worlds of Science Fiction. The story won a Hugo award in 1968. In addition, the story was adapted into a computer game in 1995.

The story is about five humans who are trapped inside the belly of the supercomputer "AM", who has destroyed the rest of the human race. AM was initially created by humanity as a tool of warfare, but eventually gained sentience. AM feels its own creation was an act of unimagineable cruelty, and therefore possesses an extreme hatred for humanity. The machine's hatred combined with its godlike power resulted in the destruction of the human race, save five humans which AM saved solely for the purpose of inflicting endless suffering.

The story is told from the perspective of one of the five humans. The humans are kept alive by AM, but subjected to physical and psychological torment. In the end, the narrator achieves a victory over AM by killing his four peers, thus ending their suffering. However, in return, AM transforms the narrator into a gelatinous blob in order to prevent him from committing suicide; hence the title, "I Have No Mouth and I Must Scream."