The 1940s in the Kingdom of Bulgaria (until 1946) and the People's Republic of Bulgaria (from 1946).

• Tsar of Bulgaria:
  • Boris III (1918–1943)
  • Simeon II (1943–1946)
• Regent:
  • Kiril, Prince of Preslav (1943–1944)
  • Bogdan Filov (1943–1944)
  • Nikola Mihov (1943–1944)
  • Todor Pavlov (1944–1946)
  • Venelin Ganev (1944–1946)
  • Tsvetko Boboshevski (1944–1946)
• Prime Minister of Bulgaria:
  • Georgi Kyoseivanov (1935–1940)
  • Bogdan Filiov (1940–1943)
  • Petar Gabrovski (acting, 1943)
  • Dobri Bozhilov (1943–1944)
  • Ivan Bagrianov (1944)
  • Konstantin Muraviev (1944)
  • Kimon Georgiev (1944–1946)

• General Secretary of the Bulgarian Communist Party:
  • Georgi Dimitrov (1948–1949)
  • Valko Chervenkov (1949–1954)
• Chairman of the Provisional Presidency: Vasil Kolarov (1946–1947)
• Chairman of the Presidium: Mincho Neychev (1947–1950)
• Prime Minister of Bulgaria:
  • Kimon Georgiev (1946)
  • Georgi Dimitrov (1946–1949)
  • Vasil Kolarov (1949–1950)

• 7 September – Bulgaria regained control of Southern Dobruja under the Treaty of Craiova.^[1]
• 14 December – Shipwreck of the Salvador, a ship carrying Jewish refugees to Palestine, in the Sea of Marmara. 230 of the 326 passengers died in the wreck.^[2]
• 24 December – The Law for the Protection of the Nation, an anti-Jewish racial law which included banning Jews from having Bulgarian citizenship, was ratified.^[2]

• March 1 – Bulgaria joined the Axis.^[3]

• June 5 – The United States declared war on Bulgaria following the latter's joined of the Axis bloc the previous year.^[4]

• December 10 – The allies conduct bombing raids over Sofia.^[5]

• August 26 – Bulgaria officially withdraws from World War II.^[6]

• September 8 - Soviet forces cross the border. They occupy the north-eastern part of Bulgaria along with the key port cities of Varna and Burgas by the next day. By order of the government, the Bulgarian Army offers no resistance.^[7][8][9]

• 18 November – Parliamentary elections were held in Bulgaria.^[10]
• 21 July – The University of Ruse was founded.^{[citation needed]}

• 8 September – A referendum was held in Bulgaria on whether to become a republic. The result were unanimously in favour of the change, with 95.6% supporting and with 91.7% voter turnout.^[11][12][13]
• 31 December – The 1946 Bulgarian census.^[14]

• Bulgaria's second constitution, the Dimitrov Constitution, came into effect. It was later replaced by the Zhivkov Constitution in 1971.^[15][16]

• 6 January – Balkantourist (the oldest still running Bulgarian tour operator) is established.^[17][18]

• 18 December – Parliamentary elections were held in Bulgaria.^[19]

• 1940
  • 2 July – Georgi Ivan Ivanov, first Bulgarian in space.^[20]
  • 8 December – Alexander Yossifov, composer and conductor.^[21]

• 1940
  • 23 March – Dimitar Stanchov, 15th Prime Minister of Bulgaria (b. 1863)^[22]
  • 10 September – Nikola Ivanov, Bulgarian general (b. 1861)^[23]
  • 23 December – Mariyka Popova, actress (b. 1866).

• Bulgaria during World War II
• History of Bulgaria
• Timeline of Bulgarian history