Sar Daq Rural District () is in Yunesi District of Bajestan County, Razavi Khorasan province, Iran. Its capital is the village of Sar Daq.
In 2007, Bajestan District was separated from Gonabad County in the establishment of Bajestan County, and Sar Daq Rural District was created in the new Yunesi District.
At the time of the 2011 National Census, the rural district's population was 3,959 inhabitants in 1,080 households. The 2016 census measured the population of the rural district as 4,979 in 1,560 households. The most populous of its 52 villages was Fakhrabad, with 2,764 people.