FK Timok 1919 (Serbian Cyrillic: ФК Тимок 1919) is a professional football club based in Zajecar, Serbia. They currently compete in the Serbian First League, the second tier of the national league system.
Founded in 1919, the club participated in the regional leagues during its early stages. They achieved their first notable success by defeating Dinamo Zagreb 3–1 in the first round of the 1973 Yugoslav Cup. The club also competed in the Yugoslav Second League for three seasons between 1981 and 1984.
After the dissolution of SFR Yugoslavia, the club advanced to the second tier for the second time, finishing bottom of the table in the 1992–93 Second League of FR Yugoslavia. They would later spend two seasons in the Second League of Serbia and Montenegro from 2002 to 2004, when they were relegated to the Serbian League East.
The club made one of its greatest achievements in its history during the 2005–06 Serbia and Montenegro Cup by eliminating Partizan away in the round of 16. After a 1–1 draw in regular time, Timok won 5–4 on penalties. The club was eventually knocked out of the competition in the quarter-finals after losing 2–0 away to Radnicki Nis.
In the 2008–09 season, the club finished second in the Serbian League East, subsequently losing 5–4 on penalties to Teleoptik (after two 1–1 draws) in the promotion playoffs. They were finally promoted to the Serbian First League after winning the 2011–12 Serbian League East title. The club spent two seasons in the second tier of Serbian football, before being relegated back to the Serbian League East in 2014.
After finishing second from the bottom in the 2017–18 Serbian League East, the club got relegated to the fourth tier and was supposed to play in the Zone League East. However, they were unable to compete due to financial reasons, causing them to go inactive. Simultaneously, the Zajecar District League champions and the Zone League East newcomers, FK Radnicki Lubnica was relocated to Zajecar and renamed to FK Timo