Aktion Gitter was a "mass arrest action" by the Gestapo which took place in Germany between 22 and 23 August 1944. It came just over a month after the failed attempt to assassinate the country's leader, Adolf Hitler, on 20 July 1944. The programme targeted former officials and members of mainstream centre and left-wing "Bourgeois" parties from the period of democratic government that were declared illegal after January 1933. Those arrested included Social Democrats and trades unionists, Liberals, Communists and Bavarian People's Party members, along with members of the old centre parties.