King Tribhuhvan Bir Bikram Shah Dev (1906-March 13, 1955) was king of Nepal from 1911 until his death. He ascended to the throne at the age of five, upon the death of his father, King Prithvi, with his mother acting as regent. At the time, however, the position of monarch was mainly titular, with real power in the country residing in the powerful, conservative Rana family, which supplied the country with its hereditary prime minister.

Tensions between the royal family and the Ranas came to a head during World War I. The Ranas wanted to join the war in support of Britain, which controlled India to the south. The Queen Mother, however, supported the army, which wanted to remain neutral. To win the military's support, the prime minister, Chandra Shumshere Rana, blackmailed the young king into ordering the troops to go to war by holding a gun to his mother's head and threatening to kill her if he did not follow his orders. Over the following years, the king was kept a prisoner in the palace and blackmailed into following the Rana's whims, which included suppressing any attempts at modernization and democratization.

By the mid-1930s, popular discontent with the Ranas led to the establishment of several movements, notably the Praja Panchayat, to overthrow the Ranas and restore power to the monarch, who had since come of age. In each instance, however, the Ranas responded harshly, banning the liberal movements and executing their leadership, even threatening to kill the king if he did not comply. Nevertheless, the king had the support of the military, which was especially important during World War II, when Nepal again allied itself with Britain. Hoping to maintain their support, the British pressured the Ranas not to harm the king.

After the war, the liberal democratic movement reorganized in the Nepali Congress Party with the support of Tribhuvan. By 1950, however, the British no longer occupied neighboring India, and the king's position became precarious. In November of that year, Tribhuvan managed to escape the palace, along with most of the royal family, and found asylum in the Indian embassy. When the king made his way to India, the Ranas responded by attempting to replace him with his grandson, Gyanendra, but this move was rejected by the general population, which revolted, and the international community, especially Britain, which refused to recognize the new king. With their authority threatened, prime minister Mohan Shamshere Jung Bahadur Rana eventually conceded to democratic reforms, and on February 18, 1951, King Tribhuvan returned as constitutional monarch. By November of that year, the prime minister resigned, ending Rana rule in the country.

Over the next few years, Tribhuvan oversaw the institution of a more democratic regime in Nepal. He died in 1955 in Zürich, Switzerland, where he was undergoing treatment for heart disease.