| 75 bliain slán ag Irisleabhar Mhá Nuad : cuntas gairid ar stair Irishleabhair ó 1898 go 1973 | Ó Fiaich, Tomás | Article in Journal | | 1973 |
| A thirteenth century poem on Armagh cathedral | | Article in Journal | | 1956 |
| Art MacCooey and his times | Ó Fiaich, Tomás | Article in Journal | | 1972 |
| Blessed Oliver Plunkett's report on the diocese of Armagh, 1670 | | Article in Journal | | 1959 |
| Brian Kiernan's lease | Ó Fiaich, Tomás | Article in Journal | | 1975 |
| Brian MacGurk, dean of Armagh, [c.1620-1713] | Ó Fiaich, Tomás | Article in Journal | | 1986 |
| Centenary of Fr. Laurence Murray, 1883-1941 | Ó Fiaich, Tomás | Article in Journal | | 1983 |
| Ceoltóiri i mBéal Feirste | Ó Fiaich, Tomás | Article in Journal | | 1946 |
| Columbanus in his own words | Ó Fiaich, Tomás | Monograph or Collective Volume | Veritas | 1974 |
| Columbanus in his own words | | Monograph or Collective Volume | Veritas | 1990 |
| Dán ar an chléir i bpríosún i mBaile Átha Cliath, 1708 | Ó Fiaich, Tomás | Article in Journal | | 1958 |
| Dán ar Phádraig Mac Síomóin | Ó Fiaich, Tomás | Article in Journal | | 1960 |
| Diocese of Armagh : sources and problems | Ó Fiaich, Tomás | Article in Journal | | 1955 |
| Early 19th-century disturbances in Creggan parish | Ó Fiaich, Tomás | Article in Journal | | 1987 |
| Edmund O'Reilly, archbishop of Armagh, 1657-1669 | Ó Fiaich, Tomás | Article in Book | | 1957 |
| Eoghan Ruadh i saol na hÉireann 1649-1942, (Athchló ar alt le Tomás Ó Fiaich, nach maireann as 'Ard Macha', Meitheamh 1943) | Ó Fiaich, Tomás | Article in Journal | | 1993 |
| Filíocht Uladh mar fhoinse don stair shóisialta san 18ú h-aois | Ó Fiaich, Tomás | Article in Journal | | 1971 |
| From Creggan to Louvain | Ó Fiaich, Tomás | Article in Journal | | 1956 |
| From Donegal to Rome by foot, boat, coach and horseback | Ó Fiaich, Tomás | Article in Journal | | 1989 |
| Gaelscrínte i gcéin | Ó Fiaich, Tomás | Monograph or Collective Volume | FÁS | 1960 |
| Gaelscrinte san Eoraip | Ó Fiaich, Tomás | Monograph or Collective Volume | Foilseacháin Ábhair Spioradálta | 1986 |
| Inscriptions in Creggan graveyard | McMahon, KevinÓ Fiaich, Tomás | Article in Journal | | 1972 |
| Irish cultural influence in Europe, 6th to 12th Century | Connolly, ThurloughÓ Fiaich, Tomás | Monograph or Collective Volume | Cultural Relations Committee of Ireland | 1967 |
| Irish monks in Germany in the late Middle Ages | Ó Fiaich, Tomás | Article in Book | | 1989 |
| Irish peregrini on the continent : recent research in Germany | Ó Fiaich, Tomás | Article in Journal | | 1965 |
| Irish poetry and the clergy | Ó Fiaich, Tomás | Article in Book | | 1975 |
| Láimhscríbhinn Ó Chúige Uladh i Chicago | Ó Fiaich, Tomás | Article in Journal | | 1957 |
| Letters on Armagh parish two centuries ago | Ó Fiaich, Tomás | Article in Journal | | 1987 |
| Letters on Armagh parish two centuries ago | Ó Fiaich, Tomás | Article in Book | | 2013 |
| Lorcán Ó Muireadhaigh, staraí | Ó Fiaich, Tomás | Article in Journal | | 1954 |
| Má Nuad | Ó Fiaich, Tomás | Monograph or Collective Volume | An Sagart | 1972 |
| Migration from Ulster to Co. Mayo in 1795-96 | Ó Fiaich, Tomás | Article in Journal | | 1989 |
| Migration from Ulster to Co. Mayo in 1795-96 | Ó Fiaich, Tomas | Article in Journal | | 2010 |
| Migration from Ulster to county Mayo 1795-96 | Ó Fiaich, Tomás | Article in Journal | | 1990 |
| MS material for diocesan and parochial history : report on the collections of sources : 2 | Ó Fiaich, Tomás | Article in Journal | | 1955 |
| Na bailéidí Béarla | Ó Fiaich, Tomás | Article in Book | | 1976 |
| Na hamhráin grá | Ó Fiaich, Tomás | Article in Book | | 1975 |
| Notes and documents. Tomás Ó Fiaich's homily at Eamon de Valera's Funeral Mass, 1975 | Ó Fiaich, Tomás | Article in Journal | | 2017 |
| Oilibhéar Pluincéid | Ó Fiaich, Tomás | Monograph or Collective Volume | Foilseacháin Ábhair Spioradálta | 1976 |
| Oliver Plunkett, 1 : Ireland's new saint | Ó Fiaich, Tomás | Monograph or Collective Volume | Veritas | 1975 |
| Oliver Plunkett, part I : Ireland's new saint; part II : in his own words | Forristal, DesmondÓ Fiaich, Tomás | Monograph or Collective Volume | Our Sunday Visitor by arrangement with Veritas Publications (Dublin) | 1975 |
| Ón Chreagán go Ceann Dubhrann : aistí le Tomás Ó Fiaich | Ó Fiaich, Tomás | Monograph or Collective Volume | An Clóchomhar | 1992 |
| Parish priests of Armagh since the Reformation | Ó Fiaich, Tomás | Article in Book | | 2013 |
| Parish priests of Mullaghbawn | Ó Fiaich, Tomás | Article in Journal | | 1974 |
| Poets and scholars of Creggan Parish | Ó Fiaich, Tomás | Article in Journal | | 1986 |
| Pól Ó hUiginn | Ó Fiaich, Tomás | Article in Journal | | 1976 |
| Priests of Armagh, 1834-2013 | Ó Fiaich, Tomás | Article in Book | | 2013 |
| Rededication of St Mary’s Church, Mullaghbawn 4th April, 1982 | Ó Fiaich, Tomás | Article in Journal | | 1990 |
| Republicanism and separatism in the seventeenth century | Ó Fiaich, Tomás | Article in Book | | 1971 |
| Richard Weston agus 'Beir mo bheannacht go Dundalk | Ó Fiaich, Tomás | Article in Journal | | 1970 |
| Saint Colmcille in Ireland and Scotland | Ó Fiaich, Tomás | Article in Book | | 1963 |
| Saint Oliver of Armagh : the life of St Oliver Plunkett | Ó Fiaich, Tomás | Monograph or Collective Volume | Veritas | 1981 |
| Saint Oliver Plunkett and the diocese of Raphoe | Ó Fiaich, Tomás | Article in Journal | | 1975 |
| Saothar Mháire mar fhoinse don stair shóisialta | Ó Fiaich, Tomás | Article in Book | | 1974 |
| Scríbhinní Mháire mar fhoinse don stair shóisialta | Ó Fiaich, Tomás | Article in Book | | 1992 |
| Sources for Irish social history, 1750-1850 | Ó Fiaich, Tomás | Article in Journal | | 1957 |
| St Kilian : his Irish background and posthumous influence | Ó Fiaich, Tomás | Article in Book | | 1999 |
| St Kilian : his Irish background and posthumous influence | Ó Fiaich, Tomás | Article in Journal | | 1989 |
| St Malachy in life and death | Ó Fiaich, Tomás | Article in Book | | 2013 |
| St Patrick and Armagh | Ó Fiaich, Tomás | Article in Journal | | 1995 |
| St Patrick and Armagh | Ó Fiaich, Tomás | Article in Journal | | 1961 |
| St. Kilian : his Irish background and posthumous influence | Ó Fiaich, Tomás | Article in Journal | | 1989 |
| St. Patrick and Armagh | Ó Fiaich, Tomás | Article in Journal | | 1958 |
| Stair Chumann na Sagart | Ó Fiaich, Tomás | Article in Journal | | 1988 |
| Survey of recent publications : III, Ecclesiastical history | Ó Fiaich, Tomás | Article in Journal | | 1954 |
| The 1766 religious census for some county Louth parishes | Ó Fiaich, Tomás | Article in Journal | | 1960 |
| The 1766 religious census for some county Tyrone parishes | | Article in Journal | | 1961 |
| The appointment of Bishop Tyrrell and its consequences | Ó Fiaich, Tomás | Article in Journal | | 1955 |
| The appointment of blessed Oliver Plunket to Armagh | Ó Fiaich, Tomás | Article in Journal | | 1958 |
| The beginnings of Christianity (5th and 6th centuries) | Ó Fiaich, Tomás | Article in Book | | 1967 |
| The Catholic clergy and the independence movement | Ó Fiaich, Tomás | Article in Journal | | 1970 |
| The church of Armagh under lay control | Ó Fiaich, Tomás | Article in Journal | | 1969 |
| The clergy and Fenianism, 1860-70 | Ó Fiaich, Tomás | Article in Journal | | 1968 |
| The contents of Mac Carthaigh's Book | Ó Fiaich, Tomás | Article in Journal | | 1950 |
| The early period | Ó Fiaich, Tomás | Article in Book | | 1991 |
| The fall and return of John Macmoyer | Ó Fiaich, Tomás | Article in Journal | | 1958 |
| The Irish bishops and the conscription issue 1918 | Ó Fiaich, Tomás | Article in Journal | | 1968 |
| The Irish Bishops and the Conscription Issue, 1918 | Ó Fiaich, Tomás | Article in Journal | | 2019 |
| The language and political history | Ó Fiaich, Tomás | Article in Book | | 1969 |
| The monastic life in early Christian Ireland | Ó Fiaich, Tomás | Article in Journal | | 1969 |
| The North and Young Ireland | Ó Fiaich, Tomás | Article in Journal | | 1998 |
| The O'Neills of the Fews | Ó Fiaich, Tomás | Monograph or Collective Volume | Cumann Seanchais Árd Mhaca | 2003 |
| The O'Neills of the Fews | Ó Fiaich, Tomás | Article in Journal | | 1977 |
| The Parish of Kilmore | Ó Fiaich, Tomás, d.1990 | Article in Journal | | 2010 |
| The political and social background of the Ulster poets | Ó Fiaich, Tomás | Article in Book | | 1970 |
| The political and social background of the Ulster poets | Ó Fiaich, Tomás | Article in Book | | 1970 |
| The priesthood of St Oliver | Ó Fiaich, Tomás | Article in Journal | | 1975 |
| The primacy in the Irish Church | Ó Fiaich, Tomás | Article in Journal | | 2006 |
| The registration of the clergy in 1704 | Ó Fiaich, Tomás | Article in Journal | | 1971 |
| The Schottenklöster in southern Germany | Ó Fiaich, Tomás | Article in Journal | | 2001 |
| The son of Sir Phelim O'Neill | Ó Fiaich, Tomás | Article in Journal | | 1955 |
| The Ulster poetic tradition in the 19th century | Ó Fiaich, Tomás | Article in Book | | 1972 |
| The Ulster poetic tradition in the 19th century | Ó Fiaich, Tomás | Article in Journal | | 2003 |
| Tomás Ó Fiaich's letters from Louvain : letters, 1950-1952, from Tomás Ó Fiaich, St Anthony's College, Louvain, to his father, Patrick Fee, Anamar | McMahon, KevinÓ Fiaich, Tomás | Monograph or Collective Volume | Cullyhanna Community Enterprises | 1994 |
| Tombstone inscriptions in Drumglass cemetery | Ó Coinne, SeánÓ Fiaich, Tomás | Article in Journal | | 1974 |
| Turas na dTaoiseach nUltach as Éirinn = From Ráth Maoláin to Rome : Tadhg Ó Cianáin's contemporary narrative of the journey into exile of the Ulster chieftains and their followers, 1607-8 (The so-called 'Flight of the Earls') | Ó Cianáin, Tadhg, c.1575-1610 | Monograph or Collective Volume | Pontifical Irish College | 2007 |
| Uí Cruinn : a lost Louth sept | Ó Fiaich, Tomás | Article in Journal | | 1951 |
| Virgil's Irish background and departure for France | Ó Fiaich, Tomás | Article in Journal | | 1985 |
| Virgils Werdegang in Irland und sein Weg auf den Kontinent | Ó Fiaich, Tomás | Article in Book | | 1985 |
| Who succeeded Blessed Oliver Plunkett? | Ó Fiaich, Tomás | Article in Journal | | 1956 |