The Esperanto flag (or verda stelo, literaly "green star") is composed of a green background with a white square in the upper lefthand corner, which in turn contains a green star. The green field symbolizes hope, the white symbolizes peace and neutrality, and the five-pointed star represents the five continents (as traditionally counted). It is called by Esperantists the "Verda Stelo" (Green Star).

By recommendation of the board of the World Esperanto Association, the flag should have the following proportions. The ratio of the width of the flag to the height of the flag to a side of the white square should 3 to 2 to 1. The ratio of a side of the white square to the radius of a circle enclosing the star should be 10 to 3.5.

Some Esperanto speakers consider the traditional flag too nationalistic for an international language, so many organizations no longer recommend its use and, instead, fly a new version: the jubilea simbolo (jubilee symbol, two green "E"s facing each other on a white field), created in 1987 by a Brazilian Esperantist. On the other hand, this new flag is derogatively called the melono (melon) by some.

Most Esperantists, however continue to hold the verda stelo dear as a symbol of international or supranational solidarity. Sometimes, Esperanto travellers will display the flag to make it easier to meet other Esperanto speakers.

See also: Esperanto culture