The Saudi Railways Organization (SRO) (Arabic: المؤسسة العامة للخطوط الحديدية‎), operated between 1966 – 2021, was one of two state-owned companies that operated Saudi Arabia's rail network along with Saudi Railway Company. The SRO operated a network of railways with a total length of approximately 1,380 kilometers. The network consists of two main lines. A 449 km passenger line that links Dammam with Riyadh, and a 556 km freight line that connects the King Abdul Aziz Port in Dammam with Riyadh. In addition, about 373 km of auxiliary lines branch main lines and connect some industrial and agricultural areas, and military sites, with export ports and residential areas.

The merger of the two companies, SAR and SRO, have been completed in April 2021, from this date all railway network is operated by the Saudi Arabia Railways.