Fudbalski Klub Radnik, commonly known as Radnik Bijeljina, was first established in June 1945, at the end of the Second World War. The name 'Radnik' translates literally to 'Worker'. Based in the city of Bijeljina, the club have often competed in the lower divisions of the various league structures they have been a part of, but have also enjoyed occasional success.
In 1948, the team became Tuzla District champions and a year later they enjoyed a cup run, reaching the last 32 of the Yugoslav Cup. The 1971-72 season saw Radnik Bijeljina become regional champions in the Republic League of Bosnia and Herzegovina and they went on to beat FK Sloga in a promotion playoff. As a result, they gained promotion to the Yugoslav Second League for the first time.
After the dissolution of Yugoslavia, Radnik Bijeljina competed in the Republika Srpska First League and won the league title in 1998-99, marking the club's greatest league achievement to date. Since the formation of the Premier League of Bosnia and Herzegovina, the team have failed to achieve significant league success and have spent much of their time in the country's second tier. They first reached the top division in 2005, after being crowned as champions of the second division, but were subsequently relegated in 2006-07. They were crowned second tier champions once more in 2011–12, gaining promotion back the Premier League in the process. In addition, the 2009-10 and 2012-13 seasons saw the club lift the Republika Srpska Cup, after beating Kozara Gradiška and Borac Banja Luka, respectively, in the finals.
Over the years, a number of Bosnia and Herzegovina international players have played for the side, including the likes of Husref Musemić, Branimir Bajić, Nenad Kutlačić and Velibor Vasilić.
Radnik Bijeljina play their home matches Gradski Stadion. It is currently able to hold a capacity crowd of 6,000 fans.