SOME SIGNIFICANT DATES IN THE LIFE OF THE SCHOOL.
| YEAR | MAJOR EVENT/OCCASION |
|---|---|
| 1962 | The school started as a single stream Day school with funding from Sisters of mercy and the Kenyan government. Inititially it occupied buildings of the older Primary school section of Our Lady of Mercy Primary School, with both sections under one Head-teacher. |
| 1965 | First 18 candidates sat for Cambridge Certificate of Education |
| 1966 | The school became a girl's only school therefore a separate entity from the primary school with its own Head-Teacher. |
| 1974 | The school became a government maintained secondary school giving grants-in-aid for recurrent expenses as well as paying Teachers' salaries. The government gave grants for the construction of a science laboratory while a German funding agency gave funds for Home-science unit |
| 1980s | Negotiations with Nairobi City Council began towards getting one of the plots earmarked for primary school in the Nairobi South B development plan in order to expand and admit more students in both schools. |
| 1980s | Parents Teachers Association was set up. |
| 1985 | Current School Plot was allocated to Catholic Archdiocese of Nairobi. |
| 1987 | 8th July- His Excellency Daniel Arap Moi presided a Fund-raising harambee held in the primary school grounds. In the month of September, construction of the first phase of the current school began with help of the funds. |
| 1989 | The school became a double stream secondary school. 13th April- the school moved to its current site from the facilities it occupied for 27 Years in the same building as Our Lady of Mercy Primary school-Nairobi South. |
| 1992 | A second science laboratory, library and classroom were built with the help of parents. |
| 1997 | Construction of the school hall and Kitchen began and was built using funds from parents, school walks, dinner dance and school luncheon. |
| 2001/2002 | School's perimeter wall was Constructed. |
| 2005 | School bus was Purchased by Parents. St. Margaret's Chapel was built by Fr. George Smyth and Our Queen of Peace Catholic Parish in Honor of his Mother- Mrs. Margaret Symth. |
| 2008 | The school became a triple stream secondary School with the help of The ministry of education's Constituency Development Fund and Parents |
| 2010 | A further three classrooms were built with the help aid of parents. |
| 2011 | Basketball Court was built by Fr. John Slinger and Our Lady Queen of Peace Catholic Parish- Nairobi South. |
| 2012 | The school celebrated a 50 year Golden Jubilee for its existence and service to the community. |
| 2015 | The school became a full boarding Girl school with construction of the dormitory still on-going. |
| 2015 To date. | In August the school Receives a new principal, Mrs. Kiruja Jayne, the Former school's Deputy Principal. MAY GOD BLESS OUR LADY OF MERCY. |