Zrenjanin or Petrovgrad is a city located in the eastern part of Vojvodina, Serbia. It is the administrative centre of the Central Banat District. The city’s population is 76,511, while the Zrenjanin county has 123,362 inhabitants (2011 census data).

Zrenjanin is the largest city in the Serbian Banat, the third largest city in Vojvodina (after Novi Sad and Subotica) and the sixth largest city of Serbia.

The city was named after Zarko Zrenjanin (1902–1942) in honour and remembrance of his name in 1946. He was one of the leaders of the Vojvodinian Communists and Partisans. The former Serbian name of the city was Beckerek or Veliki Beckerek. In 1935 the city was renamed to Petrovgrad in honor of king Peter I of Serbia. It was called Petrovgrad from 1935 to 1946.