911, sometimes written 9-1-1, is an emergency telephone number for Argentina, Canada, Dominican Republic, Jordan, Mexico, Pakistan, Palau, Panama, the Philippines, Sint Maarten, the United States, and Uruguay, as well as the North American Numbering Plan (NANP), one of eight N11 codes. Like other emergency numbers around the world, this number is only intended for use in emergency circumstances. Using it for any other purpose is a crime in most jurisdictions. Penalties for abuse or misuse of 911 can range from probation or community service to fines and jail time. Offenders can also be ordered to undergo counseling and have their use of telephones restricted or suspended for a period time as a condition of probation.

An emergency telephone number is a number that allows a caller to contact local emergency services for assistance. The emergency number differs from country to country; it is typically a three-digit number so that it can be easily remembered and dialed quickly. Some countries have a different emergency number for each of the different emergency services; these often differ only by the last digit.