The 192 members of the Universal Postal Union are listed below in alphabetical order, with the date of membership. Members are the Vatican City and the 193 UN members except Andorra, the Marshall Islands, the Federated States of Micronesia, and Palau. The newest member is South Sudan, which joined on 4 October 2011. Before 10 July 1964, states became members of the UPU by ratifying the latest version of the Treaty of Bern. After this date, states become members by ratifying the Constitution of the Universal Postal Union, which incorporated the Treaty of Bern and added provisions to it. Three states which were party to the Treaty of Bern in 1964, and hence members of the UPU, and which have signed but never ratified the Constitution are the Dominican Republic, Honduras, and Sudan. These states are deemed to have "tacitly ratified" the agreement due to their continued participation in the UPU. Also included as members are two "joint memberships" for dependent territories (one for the British overseas territories and one for the Caribbean constituent countries of the Kingdom of the Netherlands (Aruba, Curaçao and Sint Maarten), originally as Netherlands Antilles). Dependent territories are not permitted to ratify the UPU Constitution, but because the Treaty of Bern allowed for dependencies to join the UPU, listing these members separately as "Colonies, Protectorates, etc.", the Constitution of the Universal Postal Union grandfathered them when membership was restricted to sovereign states. However, neither the British nor the Dutch entities ratified the Treaty of Bern separate from the ratifications of the United Kingdom and the Kingdom of the Netherlands, respectively. By virtue of article 23 of the UPU Constitution, other dependencies of UPU member states are covered by its membership. Territories covered by a sovereign member state are listed under that country.

{{Legend|#00FF00|Member states both through their sovereign state and as individual members}} {{Legend|#FFFF00|Observer states}} {{Legend|#0080FF|Non-member states represented by a member state|undefined | upload.wikimedia.org/wikipedia/commons/4/49/Universal///Postal///Union///membership.svg]

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

Y

Z

Observer states

States not participating in UPU activities

In general areas governed by organizations that are not members of the UPU, must have their international mail handled by a member state.

Entities not participating in UPU activities

States with limited recognition

These states need to have their mail routed through third countries as the UPU will not allow direct international deliveries.

Former member countries of the UPU

In the course of history a number of member countries of the UPU saw their membership lapse, due to political changes. Where there was an immediate successor state, membership would normally devolve on that state. In other cases membership lapsed.