During the last world war, the Parish Priest Rev. George Debrincat backed by the signatures of his parishioners strongly petitioned the authorities concerned to provide a school at his parish. The authorities at last granted his request towards the beginning of 1943. Dr. A.V. Laferla, then Director of Education accompanied by Mr R. Buhagiar, the then Head of Gharb went to San Lawrenz to look for suitable premises, which was in fact found and opened on 25th September, 1940 but blessed later, on 11th March 1943. The opening ceremony was conducted by the Parish Priest in the afternoon of the 14th March 1943. The Commissioner for Gozo presided. The Superintendent of Police and Mrs DePiro, Miss R. Farrugia I.P.S., Mr Buhagiar and other guests were also present. The two classes which initially started were gradually increased to seven with the full teaching complement required. The staff consisted of Ms Giovanna Cilia, acting Headteacher and two teachers Ms G. Bonnici and Ms A. Vella. It was hosted in a private house, the property of Mr Louis Mizzi. Its address was 10, Ciangura Street. 

Two years later, the school was transferred to another property of the said Mizzi, this time in Our Lady of Sorrows Street. This house served as a school for seven years. After these years, the school was again transferred to yet another house of Mr Mizzi in Fungus Rock Street.

The need for a larger school was always felt, in fact, on 14th March, 1964, a brand new school (this present building) was inaugurated by Dr Antonio Paris, then Minister of Education. It was blessed by the Bishop for Gozo, Mgr Joseph Pace. The school continued to serve its function until 1981 when it was closed down and the premises were changed to that of a hostel. In 1988, the hostel facility started to be gradually phased out. In 1999, the school was officially named Dun Salv Portelli Primary School in honour of the parish's first chaplain. This date has been included in the School Calendar as Foundation Day. Since its inception the school had various Heads and also visits from prominent personalities including Governors, Commissioners for Gozo, Ministers, Bishops and by Prof. Guido DeMarco, former President of Malta.

Today, the school has all the required facilities including well-aired and well-lighted classrooms, caretaker's room, spacious hall, backstage, a large yard, stores and fields around the school. Although small, the school participates in all educational, cultural and sports activities being organized from time to time.