Shahriar County () is in Tehran province, Iran. Its capital is the city of Shahriar.
In 2009, Malard and Qods Districts were separated from the county in the establishment of Malard and Qods Counties, respectively.
In 2018, Ferdows and Juqin Rural Districts, and the cities of Ferdowsiyeh and Vahidiyeh, were separated from the Central District in the formation of Juqin District.
At the time of the 2006 National Census, the county's population was 1,044,707 in 273,826 households. The following census in 2011 counted 624,440 people in 178,792 households. The 2016 census measured the population of the county as 744,210 in 226,011 households.
Shahriar County's population history and administrative structure over three consecutive censuses are shown in the following table.
According to the State Meteorological Organization of Tehran province, the long-term average annual rainfall of Shahriar County is approximately 217.3 mm.