999 is an official emergency telephone number in a number of countries which allows the caller to contact emergency services for urgent assistance. Countries and territories using the number include Bahrain, Bangladesh, Botswana, Eswatini, Ghana, Guernsey, Hong Kong, Ireland, Isle of Man, Jersey, Kenya, Macau, Malaysia, Mauritius, Poland, Qatar, Sudan, Saudi Arabia, Singapore, Trinidad and Tobago, Seychelles, Uganda, the United Arab Emirates, the United Kingdom, and Zimbabwe.



Most public switched telephone networks have a single emergency telephone number (sometimes known as the universal emergency telephone number or the emergency services 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.

In many countries, dialing either 1-1-2 (used in Europe and parts of Asia) or 9-1-1 (used in the Americas) will connect callers to emergency services. For individual countries, see the list of emergency telephone numbers.