Avaj District () is a former administrative division of Buin Zahra County, Qazvin province, Iran. Its capital was the city of Avaj.
In 2012, the district was separated from the county in the establishment of Avaj County.
At the time of the 2006 National Census, the district's population was 22,273 in 5,607 households. The following census in 2011 counted 26,611 people in 7,839 households.