Mohammadiyeh District () is in Alborz County, Qazvin province, Iran. Its capital is the city of Mohammadiyeh.
The village of Sharifabad was converted to the city of Sharifiyeh in 2007. Mehregan rose to city status in 2022.
At the time of the 2006 National Census, the district's population was 87,193 in 22,728 households. The following census in 2011 counted 98,658 people in 29,052 households. The 2016 census measured the population of the district as 43,898 households.