Patrick O'Farrell (1933 – 25 December 2003) was an historian known for his histories of Roman Catholicism in Australia, Irish history and Irish Australian history. He was born into an Irish Catholic family in Greymouth, New Zealand, and was educated at the Marist Brothers High School, Greymouth, and at the University of Canterbury, where he received both a Bachelor's and a Master's degree in History. Having moved to Australia in 1956, he received a PhD from the Australian National University. He was Professor of History at the University of New South Wales from 1972 till his retirement in 1990, thereafter Emeritus Professor.
Prof. O'Farrell's first interests were in Labour history with the 1964 publication of a work on Harry Holland, an early Labour Party leader in New Zealand. The appearance in 1968 of his book The Catholic Church in Australia led to his recognition as the leading historian of the Catholic Church and community in Australia. He subsequently also became well known for his major contributions to the writing of Irish history and of Irish Australian history. In addition, he made notable contributions to a public controversy over the validity or otherwise of oral history.
- Harry Holland: Militant Socialist (1964)
- The Catholic Church in Australia: A Short History 1788-1967 (1968)
- Documents in Australian Catholic History 1788-1968 (1969)
- Ireland’s English Question: Anglo-Irish Relations 1534-1970 (1971)
- England and Ireland since 1800 (1975)
- O'Farrell, Patrick (1977). The Catholic church and community in Australia : a history. West Melbourne: Thomas Nelson (Australia).
- — (1985). The Catholic Church and community : an Australian history. Kensington, NSW: New South Wales University Press.
- — (1992). The Catholic Church and community : an Australian history (3rd rev. ed.). Kensington, NSW: New South Wales University Press.
- Letters from Irish Australia 1825-1929 (1984)
- O'Farrell, Patrick (1986). The Irish in Australia. Kensington, NSW: New South Wales University Press.
- — (1993). The Irish in Australia (Revised ed.). Kensington, NSW: New South Wales University Press.
- — (2000). The Irish in Australia : 1788 to present (3rd ed.). Kensington, NSW: UNSW Press.
- — (1990). Vanished kingdoms : Irish in Australia and New Zealand. Kensington, NSW: UNSW Press.
- Through Irish Eyes: Australian and New Zealand Images of the Irish 1788-1948 (1994)
- UNSW: a Portrait (1999)
- "Patrick O'Farrell Historian 1933 – 2003". University of New South Wales. Archived from the original on 30 September 2009. Retrieved 2 August 2009.
- J. Gascoigne, Patrick O’Farrell and the Patrick O’Farrell Memorial Lecture, Journal of the Australian Catholic Historical Society 31/2 (2010/11), 108-9.
- Revised edition of The Catholic church in Australia (1968).
- Revised edition of The Catholic church and community in Australia : a history (1977).
Finnane, Mark. "Patrick O'Farrell (1933-2003)" (PDF). Proceedings of the Australian Academy of the Humanities. 28 (2003): 48–51. Archived from the original (PDF) on 11 April 2011. Retrieved 18 February 2009.