Asara District () is in Karaj County, Alborz province, Iran. Its capital is the city of Asara.
In 2008, three villages merged in the formation of the city of Asara. In 2010, the county was separated from Tehran province in the establishment of Alborz province.
At the time of the 2006 National Census, the district's population was 18,856 in 5,407 households. The 2016 census measured the population of the district as 17,150 people in 5,977 households.