Rathdown School is an independent day and boarding school in Glenageary, Dublin, Ireland operating under Church of Ireland management. For most of its history an all-girls school, it became fully co-educational in 2023. Rathdown provides pre-school, junior and senior level education. Located on a 16-acre site, about 12 kilometres from Dublin city centre, Rathdown is consistently ranked among the top schools in Ireland. The school's colours are blue and green.

Rathdown School was founded in 1973 from an amalgamation of three schools: Park House School, The Hall School and Hillcourt School, with Glengara Park School merging in 1987. The school was originally spread across three sites, in Monkstown, Glenageary and Morehampton Road in Dublin 4. In September 1974 the school consolidated at Hillcourt's site in Glenageary (although an additional branch of the Junior School continued to operate in the Morehampton Road buildings until 1978).^[1]

Rathdown has pupils from pre-school age (3 years) to Leaving Certificate level (up to around 18 years) and offers a broad range of academic subjects in small class groups. Rathdown provides seven-day boarding for pupils aged 10 – 18 years old and allows the boarders the option of returning home at weekends or remaining at the school to avail of the weekend activities. The school also runs a dedicated international programme for overseas students and short-term boarding options for day pupils. Rathdown is the only school in Ireland that uses a methodology called Mind Lab to develop thinking abilities and life skills through strategy games.^[7] Rathdown was the first school in Ireland where pupils used iPads in class.^[8]

In 2022 the school announced that it would be becoming co-educational, and would accept boys into the junior school from September 2022, and into the senior school from September 2023,^[9] and these changes proceeded on schedule, with around one third of first years in 2023 being boys.^[10]

The school is owned by a charitable trust, Rathdown School Trust, which is led by a board of governors (who are also the charity's trustees). Its operations are overseen by a board of management, composed of four governors, two parents and two teachers, with the school head attending. Both boards delegate day-to-day leadership to the head of school.^[11][12]

Rathdown students participate in An Gaisce, the National Challenge Award from the President of Ireland to young people. Annually, Rathdown sends a team of students and staff to Romania, to volunteer with Habitat for Humanity Ireland to help build houses for local families.^[13]

Students Unite for Children’s Health (SUCH) was created by Rathdown pupils to raise funds for charities.^[14]

This section does not cite any sources. (July 2021)

• Anne Yeats (Hillcourt), painter, costume and designer, daughter of William Butler Yeats and Georgie Hyde-Lees. Later taught at The Hall School.
• Megan Taylor (The Hall), figure skater and youngest Winter Olympics competitor, representing GB at the age of 11 (1932).
• Jennifer Johnston (Park House), novelist.
• Camille Souter RHA (Glengara Park), artist.
• Noelle Middleton (Hillcourt), actress.
• Annette Jocelyn Otway-Ruthven (The Hall), medieval historian and one of the earliest female academics appointed at Trinity College Dublin.
• Joan Hanham, Baroness Hanham (née Brownlow Spark) (Hillcourt), CBE, Mayor of Kensington and Chelsea.
• Vivienne McKechnie (The Hall), poet.
• Ruth Frances Long (Glengara Park and Rathdown), fantasy and romance novelist.
• Rosanna Davison, (Rathdown), Miss World 2003 and daughter of Chris de Burgh.
• Virginia McGrath (née Conolly-Carew) (Rathdown), equestrian Olympian, competed in the Three-Day Event in Atlanta in 1996, and in Sydney in 2000.
• Tamsen McGarry (Rathdown), alpine skier and first woman to represent Ireland at the Winter Olympics (2002).
• Kirsten McGarry (Rathdown), alpine skier and first woman to represent Ireland at successive Winter Olympics (2006 and 2010).
• Saskia Tidey (Rathdown), sailor and Olympian (2016).