The St. Theresa’s High School has grown from an ‘airconditioned’ bamboo walls and kerosene tin roof building to an imposing structure adding to the beauty of TPS III. The foundation stone of the School building was laid by His Eminence Valerian Cardinal Gracias on 3 rd October, 1952. Due to land difficulties however, the work was resumed only in 1954, under the able supervision of Brother Damsus Pley SVD. In the year 1955 under the able guidance of Fr. Parch SVD as its first Principal, the school started with 118 pupils on roll. St. Theresa’s became a full fledged High School in 1961 when the first batch of students were sent up for SSC examinations. By 1963, all girls sections except Std. X and XI went over to Duruelo Convent. In 1968 under the guidance of Fr. Jungblutt, the then principal, a new extension to the school was added, which provided more classrooms and a hall for the parish.