Claret High School was established in July 1966 as an exclusive boys’ school aimed at providing secondary education for young boys who were aspiring to become future Claretians. On its first year of operation, the school  opened its doors to first and second year students with Fr. Ignacio Blanco, CMF as its first director and Mr. Pedro Domingo as principal. In 1968, the school was converted into a co-educational institution.

Two very important steps were taken in 1978-1980 to address the needs of  the  growing  Claretian family. The school opened the elementary department in 1978 with Mrs. Visitacion Sanchez as principal. The following year saw the bold move of opening the Night High School. This move was intended to provide educational opportunities to the working boys and girls in the community.

The years that followed saw changes in the school’s landscape with the construction of  the Avellana building, the perimeter fence, the school gymnasium, the extension of the Xifre building, the Vilaro and Clotet buildings.

In 1993, the Night High School ceased operation due to the lack of clientele. In 1999-2000,  the school employees enjoyed the upgrading of their salaries. The years 2000-2003 saw the construction of more buildings (Gallardo & Querexeta) as well as the completion of the Claret Gymnasium.

In school year 2005-2006, the school  continued  to fulfill its mission of being  sensitive and responsive to the needs of the poor by re-opening the Night High School with Mrs. Carolina Legarte as  principal. In the same year, the school’s name was changed from Claret High School to Claret School of Zamboanga City. Since 2006, the school has been in the process of working towards PAASCU accreditation until it was granted on November 26, 2010.

Through the years, greater moves were taken to continuously upgrade the quality of education in keeping with its vision of academic excellence and values formation. In school year 2006-2007, the school adopted the Dynamic Learning Program (DLP) espoused by Dr. Ma. Victoria Bernido & Dr. Christopher Bernido.

The entire school invokes its patrons, the Immaculate Heart of Mary and St. Anthony Mary Claret, to accompany it all the way towards the fulfillment of its mission.