Shirju Posht Rural District () is in Rudboneh District of Lahijan County, in northwestern Iran's Gilan province. Its capital is the village of Bala Mahalleh-ye Naser Kiadeh.
At the time of the 2006 National Census, the rural district's population was 15,716 in 4,711 households. There were 14,107 inhabitants in 4,787 households at the following census of 2011. The 2016 census measured the population of the rural district as 12,953 in 4,896 households. The most populous of its 29 villages was Barku Sara, with 1,368 people.