Facebook, Inc. v. Duguid, 592 U.S. 395 (2021), was a United States Supreme Court case related to the definition and function of auto dialers under the Telephone Consumer Protection Act of 1991 (TCPA) to send unsolicited text messages. In a unanimous decision based on statutory interpretation of the TCPA, the Supreme Court ruled that auto dialers are defined by their function to either store or produce telephone numbers from a random or sequential number generator.