Kavanagh College is a Catholic, integrated, co-educational school serving Years 7-13 located in central Dunedin.

Kavanagh College has a roll of around 640 students and was founded in 1989 on Rattray Street on the former site of St Paul's High School, the Christian Brothers’ Junior School and St Dominic's College. This Catholic co-educational college was formed by the amalgamation of Moreau College for girls and St Paul’s High School for boys. The founding principal was Brother Vincent Jury (1989-1991). He was followed by Mr Paul Ferris (1992-2010), Mr Tracy O'Brien (2010-2019) and Mrs Kate Nicholson (2019-present). The new college was named in honour of the fourth Catholic Bishop of Dunedin, John Patrick Kavanagh.

The College’s founding religious orders - the Dominican Sisters, the Sisters of Mercy and the Christian Brothers - were the original founders of the various schools that are part of Kavanagh College’s history.

St Dominic's College was a girls school established in 1871 by the Dominican Sisters who arrived in New Zealand with the first Catholic Bishop of Dunedin, Patrick Moran. In its centenary year, 1971, there was a roll of 200 girls including 27 boarders.

Christian Brothers’ School was founded by four Irish Christian Brothers in 1876 and its name changed to Christian Brothers’ High School in 1928. It was located on the site of the present day Kavanagh College and, due to rising rolls, a new building was built in 1964 fronting onto Rattray Street and the school was renamed St Paul's High School. Primary level classes continued to operate on the Tennyson Street site as a separate school known as Christian Brothers’ Junior School. 

St Philomena's College for girls was established in 1897 by the Sisters of Mercy and started out with four pupils. The school merged with St Dominic's College in 1976 to form Moreau College which was based in South Dunedin. Prior to this, the numbers at both schools were declining and the cost of maintaining two sites for the diocese, especially in light of the age and condition of the St Dominic’s buildings, precipitated the merger of the two girls schools to form Moreau College.

St Edmund's School was established in South Dunedin in 1949 to relieve pressure on the Christian Brothers’ School in Rattray Street. When Kavanagh College was established, the senior classes at St Edmund's School transferred to the new school, while the junior students moved to other Catholic primary schools around the city and St Edmund's closed. 

Initially, due to a lack of space, the Kavanagh College junior classes were accommodated on the former Moreau College site until 1993 when a new classroom block was completed on the Rattray Street site. The new college was further developed through the 1990s adding a science laboratory, an auditorium seating 400 people as well as a remodelled library. Earlier this century, buildings and a carpark on the opposite side of Tennyson Street were purchased to enable further expansion. Two of the buildings were demolished and a green space created for recreation and sport. One of the buildings was retained and developed into additional teaching spaces.

In 2014, Kavanagh College celebrated its silver jubilee and a large mass was held at Forsyth Barr Stadium on October 26. At the end of the mass, a plaque commemorating the three founding orders of Kavanagh College was blessed and later placed at the College.