Milicja Obywatelska (Polish pronunciation: [miˈlit͡sja ɔbɨvaˈtɛlska]), in English written as Citizens' Militia and commonly abbreviated to MO, was the national police organization of the Polish People's Republic. It was established on 7 October 1944 by the Polish Committee of National Liberation, effectively replacing the pre-war police force. The Citizen's Militia would remain the predominant means of policing in Poland until 10 May 1990, when it was transformed back into Policja.
The term milicja had been adapted from the cognate term, militsiya, used in several communist countries. The term is derived from militia, which in turn claims its etymology from the concept of a military force composed of ordinary citizens. Contrary to implied meaning, in most cases it represented rather a state-controlled force used to exert political repression on the citizens, especially with its elite ZOMO squads.
Under both communist and post-communist governments, the Polish police system has traditionally operated under the auspices of national authority. Starting at the end of World War II, Poland fell under the influence of the Soviet Union. In 1948, the country's turn toward Stalinism brought the beginning of totalitarian rule, "in which one Party ruled autonomously over all sections of society". The highly centralized nature of the militia and its lack of any great power placed it largely under the control of the Security Bureau, which used it to instill fear in the local populace. Training for the force was conducted in the town of Legionowo.