The Invasion of Normandy was the invasion and establishment of Allied forces in Normandy, France, during Operation Overlord in 1944 during World War II. It was the largest invasion force in history, as well as the largest amphibious operation ever to take place.

Allied land forces that saw combat in Normandy on 6 June came from Canada, the Free French Forces, the United Kingdom, and the United States. In the weeks following the invasion, Polish forces also participated, as well as contingents from Belgium, Czechoslovakia, Greece, and the Netherlands. Most of the above countries also provided air and naval support, as did the Royal Australian Air Force, the Royal New Zealand Air Force, and the Royal Norwegian Navy.

The Normandy invasion began with overnight parachute and glider landings, massive air attacks and naval bombardments. In the early morning, amphibious landings on five beaches codenamed Juno, Gold, Omaha, Utah, and Sword began and during the evening the remaining elements of the parachute divisions landed. The "D-Day" forces deployed from bases along the south coast of England, the most important of these being Portsmouth.