"Lili Marleen" is a German love song performed by Lale Anderson which became popular during World War II throughout Europe and the Mediterranean among both Axis and Allied troops. Written in 1915 as a poem, the song was published in 1937 and was first recorded by Lale Andersen in 1939 as "Das Mädchen unter der Laterne" ("The Girl under the Lantern").  In early 1942 she recorded the song in English, the lyrics translated by Norman Baillie-Stewart, a former British army officer working for the German Auslandssendedienst. Tommie Connor also wrote English lyrics with the title "Lily of the Lamplight" in 1944.

After the occupation of Belgrade in 1941, Radio Belgrade became the German forces' radio station under the name of Soldatensender Belgrad (Soldiers' Radio Belgrade), with transmissions heard throughout Europe and the Mediterranean.

While on leave in Vienna, a lieutenant working at the station was asked to collect a pile of second-hand records from the Reich radio station. Among them was "Lili Marleen" sung by Lale Andersen, which up till then had sold around 700 copies. Karl-Heinz Reintgen, the German officer in charge of the station, began playing the song on the air. For lack of other recordings, Radio Belgrade played the song frequently.

"Lili Marleen" became a massive success, specifically on the German language OSS MO radio station Soldatensender, where it became the station's theme song

At one point the Nazi government's propaganda minister, Joseph Goebbels, ordered broadcasting of the song to stop. Radio Belgrade received letters from Axis soldiers all over Europe asking them to play "Lili Marleen" again. Erwin Rommel, commander of the Afrika Korps, admired the song and asked Radio Belgrade to incorporate it into their broadcasts. Goebbels reluctantly changed his mind, and from then on the tune was used to sign-off the broadcast at 9:55 PM.

The song was published in South Africa, in a wartime leaflet, with an anonymous English translation, as "Lili Marleen: The Theme Song of the Eighth Army and the 6th Armoured Division".

Many Allied soldiers made a point of listening to the song at the end of the day. In 1944, the Morale Operations Branch of the U.S. Office of Strategic Services (OSS) initiated the Muzak Project, musical propaganda broadcasts designed to demoralize enemy soldiers. Marlene Dietrich, the only performer who was told her recordings would be for OSS use, recorded a number of songs in German for the project, including Lili Marleen.