A rainbow flag is a multicoloured flag consisting of the colours of the rainbow. The designs differ, but many of the colours are based on the spectral colours of the visible light spectrum.

The LGBT flag introduced in 1979 is the most recognized use of a rainbow flag.

A bit of history of the flag, In the 18th century, American Revolutionary War writer Thomas Paine proposed that a rainbow flag be used as a maritime flag to signify neutral ships in time of war.

Contemporary international uses of a rainbow flag dates to the beginning of the 20th century. The International Co-operative Alliance adopted a rainbow flag in 1925. A similar flag (ca. 1920) is used in Andean indigenism in Peru and Bolivia to represent the legacy of the Inca Empire. Since 1961, the international peace flag, also known as the PACE flag, has been especially popular in Italy and to a lesser extent Europe and the rest of the world. The pride flag has represented gay pride since 1978 and evolved into a symbol of the LGBT movement. There are several independent rainbow flags in use today.