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

It has a roll of around 820 students and was founded in 1989 in Rattray St, on the former site of St Paul's High School, the Christian Brothers Junior school and St Dominic's College. The founding principal was Brother Vincent Jury (1989-1991). He was followed by Mr Paul Ferris (1992-2010), and in recent times, Mr Tracy O'Brien (2010- present).  The new college was named in honour of the fourth Catholic Bishop of Dunedin, John Patrick Kavanagh.

Kavanagh College was amalgamated into one Catholic co-educational college from the existing Moreau College for girls and St Paul's High School for boys. The senior classes of St Edmund's primary school also transferred while the junior students were accommodated in other Catholic primary schools and St Edmund's closed. Initially, due to lack of space, the junior classes were accommodated at the former site of Moreau College for girls until 1993 when a new classroom block was completed. It was further developed through the 1990's to add a Science laboratory, an auditorium seating 400 people as well as a remodelled library. Earlier this century, land and a carpark on the opposite side of Tennyson St was purchased to redevelop and add further teaching spaces.

Kavanagh College was founded by the amalgamation of three religious orders; the Dominican Sisters, Sisters of Mercy and Christian Brothers.

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. In 1976, it merged with St Philomena's College to form one high school for girls in the city.

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 on the site of the present day Kavanagh College and due to rising rolls, a new building was built in 1964 fronting onto Rattray St, and the school was renamed St Paul's High School. 

St Philomena's College was established in 1897 by the Sisters of Mercy and it started with four pupils. It merged with St Dominic's College in 1976 to form Moreau College based in South Dunedin. The numbers of both girls schools were declining and the cost of maintaining two sites for the diocese, especially in light of the age and condition of the buildings for St Dominic's 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. It was closed as Kavanagh College was established.

In 2014, the silver jubilee was celebrated and a large mass was held at Forsyth Barr Stadium on October 14. At the end of the mass, a plaque commemorating the three founding orders of Kavanagh College was blessed and later placed at the college.