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Colaiste Mhuire Cois Abhainn
Lansdowne Road, Ballsbridge
(The pursuit of excellence)
|Principal||Oonagh McCaul, Deputy Principal Pat Glover|
|Colour(s)||Royal Blue, Old Gold|
|Affiliation||Marist Order (Brothers)|
In the early 1950s, the then Archbishop of Dublin, Dr John Charles McQuaid, had invited the Marist Brothers to open a school in the Sandymount-Ballsbridge area. This was in response to the opening of a co-educational school, Sandymount High School. Co-education was anathema to Archbishop McQuaid, so he wanted to provide a Catholic option beside it. The Marists found a site at Riverside House on the banks of the River Dodder and on 8 September 1954 the first pupils entered the Brothers’ house (Brian Nesbitt being the first student to sign up and later became a teacher at the school) to begin their secondary schooling. The Brothers decided to name the school Marian College as an acknowledgment of the special place of Mary in the foundation and traditions of the Marist Brothers and as an acknowledgment that the Church had declared 1954 as the Marian Year.
Until 1999, Sandymount High School was next door to Marian College.
For the first 34 years, the College was run by a succession of Marist Brothers. In later years, lay involvement in the management and organisation of the College has grown.
The school was ranked tenth in Ireland in terms of the number of students who progressed to third level and by the types of institutions to which the students progressed. 
Rugby union is one of the schools main sports. The college fields teams in both the JCT/SCT competitions and reached the JCT final of the Cup Shield in 2008. The JCT won the Cup Shield in 1968. Water-polo is the school's most successful sport, the college having won numerous Leinster titles over the past 10 years. In 2010 the senior Gaelic team won both the Dublin and Leinster schools championships. Marian won a Leinster basketball title in 1989-90, coached by Meany and Nesbitt. The College also won national soccer cup, captained by Graham Kavanagh and coached by Robbie Cronin. Marian won the bike polo all Ireland championship in 2010.
- Declan Hughes, author and playwright
- Adrian Kennedy, FM Radio presenter
- Diarmuid Martin, Archbishop of Dublin (2004 - ) 
- Paul Ryan (Irish Rugby League International)
- Kevin O'Brien and Niall O'Brien, brothers on the Irish international cricket team.
- Noel Pearson, film and theatre producer and impresario
- Marian College Website Archived 2012-07-22 at the Wayback Machine
- "High School ranks top in State, says new league table". Retrieved 12 November 2018.
- |url=http://www.independent.ie/opinion/analysis/is-it-worth-spending-a-mint-on-your-childs-school-239636.html |title=Is it worth spending a mint on your child's school? |publisher=Irish Independent |date=10 September 2005 |last=Fitzgerald |first=Mark |accessdate=19 June 2011}}
- Ferguson, Ciara (15 October 2006). "Meeting with the maestro". Irish Independent. Retrieved 19 June 2011.