The Mačva District (Serbian: Мачвански округ, romanized: Mačvanski okrug, pronounced [mǎtʃʋanskiː ôkruːɡ]) is one of administrative districts of Serbia. It lies in the western part of Serbia, in the geographical regions of Mačva, Podrinje, Posavina, and Pocerina. According to the 2022 census, it has a population of 265,377 inhabitants. The administrative center of the Mačva District is the city of Šabac.