FK Sloga 33 (Serbian Cyrillic: ФК Слога 33) is a football club based in Petrovac, Serbia. They compete in the Serbian League West, the third tier of the national league system.
The club took part in the 1951 Yugoslav Cup, defeating Radnički Beograd 4–1 in the opening round. They met Partizan in the next phase and were defeated 15–0, as Stjepan Bobek scored eight goals for the Belgrade side.
After winning the Podunavlje Zone League in 2007, the club spent six seasons in the Serbian League West. They would finish as champions in the 2012–13 season to earn promotion to the Serbian First League, reaching the second tier for the first time in their history. In July 2016, the club withdrew from the competition due to financial reasons.
In the summer of 2016, the club was reformed and started off in the Braničevo District League, the fifth tier of Serbian football. They reached the Serbian League West in 2018, but suffered relegation in 2021.