The same tricolour, in altering variations, has been used since the 19th century as the flag of the state of Serbia and the Serb people.

[1] The son of King Stefan Vladislav (reigned 1233–1243), župan Desa, sent delegates from Kotor to Dubrovnik to bring back part of the king's treasury held at Ragusa, which they did on 3 July 1281; the inventory list included, among other things, "a flag of red and blue color".

[4] Although the color order is not known, the version with horizontal red and blue is sometimes used in medieval-themed events in modern Serbia.

[6] The Byzantines mention that there were several war flags hoisted by the Serbs at the Battle of Velbazhd (1330), and the yellow one was likely one of those.

[2] The oldest known drawing of a Serbian flag is from the 1339 map made by Angelino Dulcert; Serbia, at the time ruled by King Stefan Dušan, is represented by a white flag of a red double-headed eagle placed above the capital Skopje (Scopi).

[14] The 1835 Sretenje Constitution described the colors of the Serbian flag as bright red, white and čelikasto-ugasita (that could be translated as steelish-dark).

[16] Soon afterwards, Miloš Obrenović was requesting to the Porte that the new constitution should contain an article about the flag and coat of arms,[3] and subsequent ferman allowed Serbs to use their own maritime flag, which will have "upper part of red, middle of blue, and lower of white", which is the first appearance of the colors that are used today.

The citizens thus noticed that Serbs have their own characteristics.Serbia used the red, blue and white tricolor as a national flag continuously from 1835 until 1918, when Serbia ceased to be a sovereign state after it joined the Kingdom of Serbs, Croats and Slovenes, later known as Yugoslavia, the tricolor was a used as a Serbian civil flag, from 1918 to 1945.

Also in 1918, a Serbian flag was flown over the White House in Washington, D.C. as a show of solidarity by the U.S. towards Serbia during World War I.

The red star was nonetheless removed from the flag in 1992 by a recommendation by the Serbian parliament;[23][26] however, the coat of arms remained unchanged.

In 2004, however, the National Assembly of Serbia issued a recommendation on use of the flag and coat of arms that preferred using different symbols from the ones in the constitution.

[28] On 11 November 2010, a visual redesign of the coat of arms was enacted, which is currently used on the state flag.

[30] The flag ratio is 2 to 3 (height/width), with three equal horizontal bands of red, blue and white, each taking one third of the height.

[37] The civil flag of Serbia is constantly flown on the entrance of the National Assembly and organs of provinces and public services.