The school was founded in 1917 as an Upper Primary school named St.Mary's L. P School for the education of socially and economically backward community especially the fisher folk with the earnest leadership of Rev.Fr.Trinidad ,the Vicar of Vettucaud Parish. A Malayalam training school was also functioned along with it. Later it was stopped when SSLC was made the basic qualification for teaching primary classes. Since then it is never tired of extending its strenuous arms in pursuit of academic excellence. A further advancement to this effect was made when it was upgraded to High School in 1952. The foundation stone of the High School building, blessed by Rev.Fr.Peter Puthenpurakkal, was laid by Sri.A.J.John, the Chief Minister of Travancore- Cochin state who had granted 7.5 acres of purambokku land for the school. Rt.Rev.Dr.Peter Bernard Pereira, the Bishop of Trivandrum diocese was the prime source of inspiration, guidance and support for the construction of new school building. It was officially inaugurated by Sri.V.K.Krishna Menon. It started as a Boys' School and was switched to co-education system in 1966.The first batch of SSLC passed out in 1956. From the time of its inception the school has been striving hard to progress both academically and non-academically.

It flourished well under Sri.S.Hariharan sir, who had been the Headmaster for a period of long 17 years. He had won the State and National award for the best teacher. The school has attained consistent 100% result in SSLC for the past four years and excels in sports and games by contributing skilled and talented players to the state and national team.The Higher Secondary Section was started in1998 with one batch in Biology Science stream and one in Commerce stream. Now it has grown to a school with 5 batches for Higher Secondary, a full-fledged centre for institutionalised learning. It has good infrastructure with spacious and well-ventilated smart class rooms, well equipped laboratories,library, large playground and all other physical amenities. It provides transportation facilities for the students. In addition to this, a new building with 4 classrooms, library, laboratory and auditorium has been constructed in the year 2023-2024.From its humble beginning In 1952 with 11 teachers and modest strength the school has grown in strength and stature with more than 1000 students and 55 staff. It celebrated its centenary in 2017.This aboard of excellence is now under the blessed patronage of Most Rev.Dr.Thomas.J.Netto, the Arch Bishop of Trivandrum Latin Archdiocese.

It is headed by Smt.Mary Christalda. A, the Principal and Smt. Mary Viji. E.V, the Headmistress. They lead a team of well qualified and committed teachers who are dedicated to mould the students for the future. There is a special teacher for the differently abled students and counsellor to support students in their psychological, academical and social development. Souhrida Club, NCC (Air,Naval wing), JRC, NSS, Career guidance cell etc are functioning effectively to make our students socially committed and productive citizens. Motivational classes, awareness programmes and value education classes are organised for the students.
It is an alma mater to many eminent personalities who excelled in various walks of life. Over a century it has become an integral part of the local community, fostering academic excellence and spiritual growth. As we look to the future St.Mary's will remain dedicated to provide high quality education that prepares students to meet the challenges of an ever changing world. The community bows in prayerful gratitude before the Almighty for the innumerable blessings showered on it in the past.