Burma officially became Myanmar on 18 June 1989 , when the country’s military government changed the English name of the nation from “Burma” to “Myanmar” and adopted the new official name “Republic of the Union of Myanmar”.

The official change

On 18 June 1989, the ruling military junta (the State Law and Order Restoration Council, SLORC) issued a decree renaming the country in English from “Burma” to “Myanmar”. At the same time, they changed the English names of many cities and regions, such as Rangoon → Yangon, Prome → Pyay, and Moulmein → Mawlamyine.

The full official name became the “Republic of the Union of Myanmar,” replacing the previous “Union of Burma”. This was part of a broader campaign to replace colonial-era names with ones the regime said better reflected the country’s ethnic diversity and national identity.

Why the name “Myanmar”?

The name “Myanmar” comes from the Burmese word “Myanma” (မြန်မာ), which has been used for centuries in the Burmese language to refer to the country and its dominant ethnic group, the Bamar. The military government argued that “Myanmar” was a more inclusive, formal name that represented all ethnic groups in the country, not just the Bamar majority.

They also claimed that “Burma” was a colonial relic imposed by the British, while “Myanmar” was the authentic, indigenous name. Historically, the term “Myanma” dates back to at least the 13th century and was used in royal Burmese chronicles.

How the world reacted

Many countries and the United Nations accepted the name change and began using “Myanmar” in official contexts. However, some governments, including the United States and the United Kingdom, continued to use “Burma” for political reasons, especially in solidarity with the pro‑democracy movement led by Aung San Suu Kyi.

Even today, both names are used: “Myanmar” is the official name in most international organizations and diplomatic settings, while “Burma” is still common in media, historical contexts, and by groups that oppose the military regime.

A quick timeline

  • 1824–1948 : British colonial rule; the country is known internationally as Burma.
  • 4 January 1948 : Burma gains independence from Britain as the “Union of Burma”.
  • 18 June 1989 : Military government changes the English name to “Myanmar” and the official name to “Republic of the Union of Myanmar”.
  • 1990s–present : Most of the world uses “Myanmar,” but some countries and groups still prefer “Burma”.

So, to answer directly: Burma became Myanmar on 18 June 1989.

Bottom line :
The name change from Burma to Myanmar happened officially on 18 June 1989 under the military government, though both names are still used today depending on context and political stance.