The civil flag of Hesse consists of a bicolour of a red top and a bottom white stripe. The state flag is similar, except it is defaced with the state coat of arms in the centre, and may only be used by government departments and services. The civil flag of Hesse resembles that of Monaco's and, particularly, Indonesia's.

The colours red and white are based on that of the Ludovingian coat of arms, showing a lion with a nine fold horizontal white and red division. The coat of arms was inherited by the House of Hesse upon its split from the Duchy of Thuringia in 1247, and the flag came into use in the early modern Landgraviate of Hesse; the modern Grand Duchy of Hesse used a flag with two red stripes, as did the People's State of Hesse until 1933.

The flag of Thuringia was introduced in 1920, with its formation out of the fragmented Thuringian states (the Duchy of Thuringia had been absorbed into Saxony in 1400), as the reverse of the flag of Hesse.