Sandford School was built in 1826 in the parish of St. Peter, in what was then the semi-rural setting of Ranelagh. A chapel and residences for the chaplain and school teachers were constructed in the same year, with the entire project financed by George Sandford of Somerset. This financial support, totalling £4,000, was secured by Robert Newenham, a friend of Lord Sandford, who lived at Merton, a substantial house in the Ranelagh area, and was a lay member of the Established Church of Ireland.

The 1835 Register of Schools lists three schools on the site: Sandford School for males with 43 boys on the roll, Sandford School for females with 26 girls, and Sandford Infant School with 45 pupils. Three members of the Coombe family taught in the school, which was financed by Church funds, an endowment from George Sandford, and voluntary contributions. About half of the children paid one penny a week.

In the 19th century, enrolment peaked in the 1850s with 125 pupils on the roll, but declined as the century progressed, falling to 55 children by 1899, when Sandford had only two teachers. In 1901, Sandford Parish School became Sandford Parish National School under the National Board of Education—joining the system later than most Church of Ireland schools. Numbers grew steadily and increased further with the amalgamation of Sandford and Donnybrook Church of Ireland School in the 1960s. Two prefabs were acquired at that time to accommodate the additional classes.

A new school was built on the existing site between 1992 and 1993, with the original hall retained and upgraded. In 2009, the Department of Education and Skills approved the construction of an additional extension. All prefabs were removed, and two more classrooms were added. Two resource rooms, a secretary’s office, a Principal’s office, an extended staffroom, and a new library were also included in the project. These additions greatly enhanced the school building.

Today, the school has approximately 200 children on its roll, and staffing levels are in accordance with Department of Education and Youth regulations.