Express mail is an expedited mail delivery service for which the customer pays a premium for faster delivery. Express mail is a service for domestic and international mail, and is in most nations governed by the country's own postal administration. Since 1999, the international express delivery services are governed by the EMS Cooperative.

The Universal Postal Union is a specialized agency of the United Nations (UN) that coordinates postal policies among member nations and facilitates a uniform worldwide postal system. It comprises 192 member states and is headquartered in Bern, Switzerland.