The Top 100 Surnames in Ireland. (Please note that variants of the same surname are shown together with the percentage of the total. For example Kelly 97%, O’Kelly 3% means that 3% of the Kelly families use the "O" before the family name.) 1. Murphy 2. Kelly 97%, O’Kelly 3% 3. Walsh 94%, Walshe 6% 4. O’Connor 89%, Connor 9%, Connors 2% 5. O’Sullivan 89%, Sullivan 11% 6. Byrne 95%, O’Byrne 5% 7. O’Brien 98%, Brien 2% 8. Ryan 9. Smith 52%, Smyth 48% 10. O’Neill 92%, Neill 8% 11. O’Reilly 61%, Reilly 39% 12. M(a)cCarthy 97%, Carthy 3% 13. Doyle% 14. Brown 56%, Browne 44% 15. Murray 16. Doherty 85%, O’Doherty 12%, Dougherty 3% 17. Burke 80%, Bourke 20% 18. Lynch 19. M(a)cLaughlin 51%, M(a)cLoughlin 41%, Loughlin 6%, Laughlin 2% 20. Quinn 99%, Quin 1% 21. Kennedy 22. Moore 23. Gallagher 24. Johnston 86%, Johnson 12%, Johnstone 2% 25. Campbell 26. Brennan 27. Clarke 95%, Clark 5% 28. Wilson 29. Dunne 92%, Dunn 8% 30. Daly 99%, O’Daly 1% 31. O’Connell 88%, Connell 12% 32. Martin 33. Whelan 64%, Phelan 36% 34. Flynn 84%, O’Flynn 16% 35. M(a)cMahon 71%, Mahon 29% 36. Farrell 86%, O’Farrell 14% 37. Carroll 85%, O’Carroll 15% 38. Collins 39. Nolan 99%, O’Nolan 1% 40. Connolly 41. O’Donoghue 53%, Donohoe 21%, Donoghue 13%, Donohue 8%, O’Donohoe 3%, O’Donohue 2% 42. Thompson 97%, Thomson 3% 43. Fitzgerald 44. Hughes 45. Maguire 85%, M(a)cGuire 15% 46. O’Donnell 98%, Donnell 2% (est) 47. White 81%, Whyte 19% 48. M(a)cGrath 99%, Magrath 1% 49. Duffy 99%, O’Duffy 1% 50. Kavanagh 93%, Cavanagh 7% 51. M(a)cCormack 64%, M(a)cCormick 34%, Cormack 2% 52. O’Mahony 75%, Mahony 14%, O’Mahoney 7%, Mahoney 4% 53. Power 54. O’Callaghan 70%, Callaghan 30% 55. Stewart 91%, Stuart 9% 56. Sweeney 74%, M(a)cSweeney 26% 57. Boyle 83%, O’Boyle 17% 58. O’Shea 98%, Shea 2% 59. Brady 60. Fitzpatrick 96%, Patrick 4% 61. Healy 62. Donnelly 63. O’Donovan 76%, Donovan 24% 64. O’Leary 99%, Leary 1% 65. M(a)cKenna 93%, Kenna 7% 66. Hayes 67. Robinson 68. Graham 69. Kenny 70. Keane 99%, O’Keane 1% 71. Cunningham 72. Barry 73. Moran 74. Kane 59%, O’Kane 41% 75. Casey 76. M(a)cDonnell 97%, Donnell 3% (est) 77. Hamilton 78. Keogh 65%, Kehoe 31%, McKeogh 4% 79. Foley 80. Buckley 81. O’Keeffe 95%, O’Keefe 5% 82. Ward 83. M(a)cDonald 95%, Donald 5% 84. Mullan 46%, Mullen 41%, Mullin 12%, O’Mullan 1% 85. Reid 96%, Read 2%, Reed 2% 86. M(a)cCann 87. Curran 88. Scott 89. Roche 90. Maher 91. Griffin 98%, Griffen 2% 92. Bell 93. Sheehan 85%, Sheahan 15% 94. O’Dwyer 64%, Dwyer 36% 95. Moloney 73%, Maloney 23%, Molony 4% 96. Magee 66%, M(a)cGee 34% 97. Higgins 96%, O’Higgins 4% 98. M(a)cKeown 74%, M(a)cKeon 21%, Keown 5% 99. Cullen 100. Lyons *Survey of Irish Surnames 1992-97 by Sean J Murphy