The Diocese of Zrenjanin (Latin: Dioecesis Zrenjanensis, Serbian: Zrenjaninska biskupija / Зрењанинска бискупија, Hungarian: Nagybecskereki egyházmegye, Croatian: Zrenjaninska biskupija, German: Bistum Zrenjanin) is a Latin Church ecclesiastical territory or diocese of the Roman Catholic Church in Serbia.

The diocese is multi-ethnic and has members primarily from the sizable Hungarian and Croat communities, as well as Bulgarians, Czechs, Slovaks, and Germans.

After the collapse of Austria-Hungary, region of Western Banat was incorporated into newly formed Kingdom of Serbs, Croats and Slovenes (later known as Yugoslavia).

Until the end of Second World War, the largest number of Roman Catholics in the territory of Yugoslav Banat was of German ethnicity.

In 1986, apostolic administration was reorganized into "Diocese of Zrenjanin" and placed under metropolitan jurisdiction of Roman Catholic Archbishop of Belgrade.