Myanmar, officially the Republic of the Union of Myanmar, also known as Burma (the official name until 1989), is a country in Southeast Asia. It is the largest country by area in Mainland Southeast Asia, and had a population of about 54 million in 2017. It is bordered by Bangladesh and India to its northwest, China to its northeast, Laos and Thailand to its east and southeast, and the Andaman Sea and the Bay of Bengal to its south and southwest. The country's capital city is Naypyidaw, and its largest city is Yangon (formerly Rangoon).

Early civilisations in the area included the Tibeto-Burman-speaking Pyu city-states in Upper Myanmar and the Mon kingdoms in Lower Myanmar. In the 9th century, the Bamar people entered the upper Irrawaddy valley, and following the establishment of the Pagan Kingdom in the 1050s, the Burmese language, culture, and Theravada Buddhism slowly became dominant in the country. The Pagan Kingdom fell to Mongol invasions, and several warring states emerged. In the 16th century, reunified by the Taungoo dynasty, the country became the largest empire in the history of Southeast Asia for a short period. The early 19th-century Konbaung dynasty ruled over an area that included modern Myanmar and briefly controlled Manipur and Assam as well. The British East India Company seized control of the administration of Myanmar after three Anglo-Burmese Wars in the 19th century, and the country became a British colony. After a brief Japanese occupation, Myanmar was reconquered by the Allies. On 4 January 1948, Myanmar declared independence under the terms of the Burma Independence Act 1947.

Myanmar's post-independence history has continued to be checkered by unrest and conflict. The coup d'état in 1962 resulted in a military dictatorship under the Burma Socialist Programme Party. On 8 August 1988, the 8888 Uprising then resulted in a nominal transition to a multi-party system two years later, but the country's post-uprising military council refused to cede power, and has continued to rule the country through to the present. The country remains riven by ethnic strife among its myriad ethnic groups and has one of the world's longest-running ongoing civil wars. The United Nations and several other organisations have reported consistent and systemic human rights violations in the country. In 2011, the military junta was officially dissolved following a 2010 general election, and a nominally civilian government was installed. Aung San Suu Kyi and political prisoners were released and the 2015 Myanmar general election was held, leading to improved foreign relations and eased economic sanctions, although the country's treatment of its ethnic minorities, particularly in connection with the Rohingya conflict, continued to be a source of international tension and consternation. Following the 2020 Myanmar general election, in which Aung San Suu Kyi's party won a clear majority in both houses, the Burmese military (Tatmadaw) again seized power in a coup d'état. The coup, which was widely condemned by the international community, led to continuous ongoing widespread protests in Myanmar and has been marked by violent political repression by the military, as well as a larger outbreak of the civil war. The military also arrested Aung San Suu Kyi and charged her with crimes ranging from corruption to the violation of COVID-19 protocols, all of which have been labeled as "politically motivated" by independent observers, in order to remove her from public life.

Myanmar is a member of the East Asia Summit, Non-Aligned Movement, ASEAN, and BIMSTEC, but it is not a member of the Commonwealth of Nations despite once being part of the British Empire. The country is very rich in natural resources, such as jade, gems, oil, natural gas, teak and other minerals, as well as also endowed with renewable energy, having the highest solar power potential compared to other countries of the Great Mekong Subregion. However, Myanmar has long suffered from instability, factional violence, corruption, poor infrastructure, as well as a long history of colonial exploitation with little regard to human development. In 2013, its GDP (nominal) stood at US$56.7 billion and its GDP (PPP) at US$221.5 billion. The income gap in Myanmar is among the widest in the world, as a large proportion of the economy is controlled by cronies of the military junta. Myanmar is one of the least developed countries; as of 2020, according to the Human Development Index, it ranks 147 out of 189 countries in terms of human development. Since 2021, more than 600,000 people were displaced across Myanmar due to the surge in violence post-coup, with more than 3 million people in dire need of humanitarian assistance.