The FP-45 Liberator is a handgun manufactured by the United States military during World War II for use by resistance forces in occupied territories.

The Liberator was shipped in a cardboard box with 10 rounds of .45 ACP ammunition, a wooden dowel to remove the empty cartridge case, and an instruction sheet in comic strip form[5] showing how to load and fire the weapon.

It was believed that if vast quantities of these handguns could be delivered into Axis-occupied territory, it would have a devastating effect on the morale of occupying troops.

It was hoped that the thought of thousands of these unrecovered weapons potentially in the hands of the citizens of occupied countries would have a deleterious effect on enemy morale.

[7] General Dwight D. Eisenhower's staff never saw the practicality in mass dropping the Liberator over occupied Europe, and authorized distribution of fewer than 25,000 of the half million FP-45 pistols shipped to Great Britain for the French resistance.

The Army then turned 450,000 Liberators over to the Office of Strategic Services (OSS), which preferred to supply Resistance fighters in both theatres with more effective weapons whenever possible.

French use of the FP-45 remains undocumented, however, a first-hand account of an assassination with an FP-45 exists from German military policeman Niklaus Lange.