Hajjilar () is a city in, and the capital of, Hajjilar District in Chaypareh County, West Azerbaijan province, Iran. It also serves as the administrative center for Hajjilar-e Jonubi Rural District.
At the time of the 2006 National Census, Hajjilar's population was 1,291 in 370 households, when it was a village in Hajjilar Rural District of the former Chaypareh District in Khoy County. The following census in 2011 counted 1,560 people in 428 households, by which time the district had been separated from the county in the establishment of Chaypareh County. The rural district was transferred to the new Hajjilar District and renamed Hajjilar-e Jonubi Rural District. Hajjilar was transferred to Hajjilar-e Shomali Rural District created in the same district. The 2016 census measured the population of the village as 1,394 people in 434 households. It was the most populous village in its rural district.
After the census, Hajjilar was converted to a city.