The 1944 Bulgarian coup d'état, also known as the 9 September coup d'état, was a coup that overthrew the government of Kingdom of Bulgaria carried out on the eve of 9 September 1944. During the People's Republic of Bulgaria it was called using the propaganda term People's Uprising of 9 September – on the grounds of the broad unrest and Socialist Revolution – as it was a turning point politically and the beginning of radical reforms towards Soviet-style socialism.

Simeon Borisov Saxe-Coburg-Gotha is a Bulgarian politician who reigned as the last tsar of the Kingdom of Bulgaria as Simeon II from 1943 until 1946. He was six years old when his father Boris III of Bulgaria died in 1943. Royal power was exercised on his behalf by a regency council led by Simeon's uncle Kiril, Prince of Preslav, General Nikola Mihov and prime minister, Bogdan Filov. In 1946 the monarchy was abolished by referendum, and Simeon was forced into exile.