Bijeljina is a city and municipality located in the Republika Srpska entity of Bosnia and Herzegovina. It serves as the provincial center of Semberija, which is a geographic region situated in the northeastern part of the country.
As of 2013, the city had a population of 107,715 inhabitants. This demographic size makes Bijeljina the sixth largest city in Bosnia and Herzegovina and the second largest city within the Republika Srpska entity, following Banja Luka.