Operation Avalanche was the codename for the Allied landings near the port of Salerno, executed on 9 September 1943, part of the Allied invasion of Italy during World War II. The Italians withdrew from the war the day before the invasion, but the Allies landed in an area defended by German troops. Planned under the name Top Hat, it was supported by the deception plan Operation Boardman.

Salerno is an ancient city and comune (municipality) in Campania, southwestern Italy, and is the capital of the namesake province, being the second largest city in the region by number of inhabitants, after Naples. It is located on the Gulf of Salerno on the Tyrrhenian Sea. In recent history the city hosted Victor Emmanuel III, the King of Italy, who moved from Rome in 1943 after Italy negotiated a peace with the Allies in World War II, making Salerno the capital of the "Government of the South" and therefore provisional government seat for six months. Some of the Allied landings during Operation Avalanche occurred near Salerno.