Holy Child School, Killiney was founded in 1948.  Killacoona House which had operated as the County Hotel was acquired by the Society of the Holy Child Jesus (SHCJ) for a school and convent.  The house stands on a cliff overlooking Killiney Bay.

The school began with thirty four students; twelve boarders and twenty two day pupils.  Student numbers increased and in 1950 the building of an extension of six new clasrooms, four dormitories and a hall/gym began.

The school was officially recognized by the Department of Education in 1954 and in June of that year the school presented its first six candidates for the Leaving Certificate exam.

Science in the school was in its infancy and although a laboratory was planned there was as yet only a small room equipped with a kettle and one bunsen burner.  In 1955, the plans became a reality and a laboratory and domestic science room were built over the school hall.

The property was extended in the mid 1950's by the purchase of the adjoining houses, Kildimo Lodge and Little Anstice - now named Kilmuire, home to the present SHCJ community.

In 1961 permission was granted by the Provincial Council to build a chapel.  This was a great joy for the community.  On August 5th, 1962 Archbishop McQuaid blessed the chapel under the patronage of our Lady of Divine Grace and said the first Mass there.

A new concert hall was built in 1968, the Cornelia Connelly Hall. The science laboratories were extended and equipped at this time also.

In 1973, after the announcement that the Sacred Heart School in Monkstown was to close, the Holy Child Sisters went into collaboration with the Sacred Heart Sisters and it was agreed that the Junior School would continue at Monkstown and that Killiney would take the Senior School students.  When a year or two later Monkstown closed the Junior School, Killliney reverted to taking girls from the age of nine years.  During this time it was decided that the students should be prepared for the Intermediate Certificate examinations so the GCE O Levels were discontinued.

Boarding ended in 1976 and the school became entirely a day school.

The Killiney Parents' Association (KPA) was established in 1986 and the first Board of Management was appointed in 1989.  It was in 1996 that the first Lay Principal, Mrs. Vera Collins, was appointed.  This was the year the school celebrated its Golden Jubilee.

The all weather astroturf hockey pitch was completed in 2004 and the computer room was re-equipped. 

in 2005 it was decided to close the three Junior Classes in order to provide extra space and facilities for the Secondary School.

In 2007 on the retirement of Mrs. Vera Collins, Mrs. Gerardine Hackett was appointed Principal.