Myanmar, officially the Republic of the Union of Myanmar and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has a population of about 55 million. It is bordered by India and Bangladesh 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 and 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 Assam, the Lushai Hills, and Manipur 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 been checkered by continuing unrest and conflict to this day. 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 in order to remove her from public life, and charged her with crimes ranging from corruption to violation of COVID-19 protocols; all of the charges against her are "politically motivated" according to independent observers.

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. Myanmar is a Dialogue Partner of the Shanghai Cooperation Organization. The country is very rich in natural resources, such as jade, gems, oil, natural gas, teak and other minerals, as well as 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. Since 2021, more than 600,000 people have been displaced across Myanmar due to the civil war post-coup, with more than three million people in dire need of humanitarian assistance. According to the United Nations High Commissioner for Refugees (UNHCR), there are over 1.3 million people counted as refugees and asylum seekers, and 3.5 million people displaced internally as of December 2024.