The flag of Republika Srpska was adopted on 24 November 1992. The flag is a rectangular tricolour with three equal horizontal bands of red, blue and white.
While the Constitutional Court of Bosnia and Herzegovina declared the coat of arms of Republika Srpska unconstitutional, claiming that it did not represent the non-Serb ethnicities living in the entity, the flag was deemed to be in line with the constitution. The court ruled that though the combination of the colours relates to the Serbian tricolor, the use of red, blue and white are considered to be pan-Slavic colours as well.
The Serbian tricolor has been used as the basis for other flags, most notably as Serbia's official flag. Montenegro has also used the Serbian tricolor with varying shades of blue. Under communist Yugoslavia, the republics of Serbia and Montenegro had flags of same design and colors. Montenegro changed its flag in 1993 by altering the proportion and shade of blue in its flag and used this flag until 2004.