|20th August 1961|
|Rev Mother Isabel & Rev Mother Josephine - Ex Superior general of the congregation started a nursery school in a rented building with the aim of propagating Mother Mariam Theressia’s aim at Olavakkode, Palghat.
|New building constructed and school shifted.|
|4th April 1964|
|Lower primary section granted recognition Rev. Sr. Servia the first official Headmaster.|
|1st June 1965|
|New building and the school completely shifted Rev. Sr. Lucy Joseph the Headmistress.|
|19th Aug 1966|
|Formal inauguration of the school by V.K.Sethumadhavan, Divisional Superintendent Southern Railway.|
|1969 to 1979|
|Rev. Sr. Marianus the Headmistress, recognition granted upto 10th Std. St.Thomas Convent Girls High School.|
|The first batch of SSLC students passout with 100% results.|
|1979 – 1982|
|Rev. Sr. Sila the Headmistress co education upto the VII std.|
|1982 – 1991|
|Rev. Sr. Regi Paul the Headmistress, grew from strength to strength. Computer classes introduced.|
|1991 – 2004|
+ Sr. Sila 2nd innings at St. Thomas Convent Girls High School.
+ New Open Air Auditorium constructed.
+ New Library
+ New administrative block with conference hall on top
+ New gate
|+ Introduction of Higher Secondary, takes over as Principal 1st batch of Higher Secondary passes out with 100% results.
+ Introduction of co-education
|+ Becomes St.Thomas Convent Higher Secondary School
+ New building for the Higher Secondary - Inauguration by the Collector of Palakkad Mr.Anil X and blessed by Bishop Mar Jacob Manathodath.
|Construction of Prayer and chapel with counseling facilities - Blessed by Fr. Davis Chakkumpeedika|
|2004 - 2009|
| + Sr. Ansa Paul the new Principal
+ Introduction of the Edu-sat
|+ Construction of Seminar Hall and Computer Lab for Higher Secondary
+ Construction of a Basket Ball Court - Blessed by Father Jose Potteparambil Vicar St.Joseph’s Church. Unveiled by Sr. Provincial Rev. Sr. Prasanna Thattil an auspicious start by T.K.Sheshadri Basketball Player
|2009 - 2012|
|Sr.Manjula - the New Principal|
|+ Rev.Sr.Sila comes back - Her 3rd Innings begin
+ Golden Jubilee preparations begin
+ Inauguration, declaration & unveiling of golden jubilee logo, programmes chartered out for the entire year.
+ Rev. Dr. Sr. Pushpa Provincial Superior Mariam Province 15th Aug. 2012 does the honours.
+ Introduction of Smart Classes from 2013 decision & agreement signed.