Wadden (Wadding)
- Uaidín
Waddick (Waddock) - Mac Mhadóc
(Mac) Wade - Mac Uaid
Waldron (Mac Bhaildrín) - de Bhaldraithe
Walker - Mac Siúlaí
Wall - de Bhál
Wallace (Wallis) - Bhailis
Walrick - Mag Ualraig
Walse(e) - Breatnach
(Mac) Walter(s) - Ualtair
Walton - de Bháltún
(Mac) Ward - Mac an Bhaird
(Mac) Warnock - Mac Giolla Mhearnóg
Warrin (Warren) - Ó Murnáin
Waters - Ó hUisce
Watterson - Mac Uaitéir
Waterson - Mac Uaitéir
Watson - Mac Uait
Mac Watters - Mac Uaitéir
Watts - Mac Uait
Wayland - Ó Faoláin
Weadock (Weddick) - Mac Mhadóc
Weaver - Mac an Fhíodair
Mac Weeney - Mac Mhaonaigh
(Mac) Weir (Wear) - Mac an Mhaoir
Welch - Breatnach
Weldon - Béalatún
Weldon - Ó Mhaoldúin (Fear Manach)
Wellesley - Mac Bhalronta
Welsh - Breatnach
Wesley (Wesley) - Mac Bhalronta
Weston - Uastún
Whalon (Whealon) - Ó Faoláin
Whan - Mac Mhíolchon
(Mac) Whannell - Mac Dhónaill
Mac Whannon - Ó Buacháin
Wharton - Ó hArrachtáin
Whearty - Ó Faghartaigh
Whelan - Ó Faoláin
Whelan - Ó Fialáin (Fear Manach)
(O) Whelehan - Ó Faoileacháin
Whelton - Ó hUallacháin
Mac Wherter - Mac Artair
Whin - Mac Shuibhne
Mac Whinney - Mac Shuibhne
Mac Whirter - Mac Artair
Mac Whiston - Mac Úistín
Whitaker - Mac Uitheachair
Whitcomb - Mac Thiarnáin
White - de Faoite
Mac White - Mac Faoitigh
White - Ó Banáin
Whit(e)lock (Whitehead) - Ó Ceannuáin
Whitesteed - Ó hEachuáin
Whitley - de Fuitléigh
Whitney - de Fuitnigh
Whitty - de Fuite
Whitty - Mac Faoitigh
Wholey - Ó hUallaigh
Whoolehan - Ó hUallacháin
Whoriskey - Ó Fuaruisce
Mac Whorter - Mac Artair
Whyte - Ó Banáin
Wier (Weir) - Mac an Mhaoir
(Mac) Wigin - Mag Uiginn
Wigmore - de Uigeamór
Wilhair - Mac Giolla Chathair
Mac Wilkin - Mac Uilcín
Wilkin(son) - Mac Uilcín
Mac William(s) - Mac Uilliam
Williams(on) - Mac Uilliam
Mac Willie - Mac Uilí
Willis (Wills) - Uilis
Wilmit (Wilmott) - Uilmit
Willmore - Mac Liammóir
Wilson - Mac Liam
Windham - Ó Gaoithín
Windle - Uingil
Wingfield - Uingséil
Wingle (Winkle) - Uingil
Winn - Ó Gaoithín
Wrynn - Mag Bhroin
Winters - an Gheimhridh
Wire - Mac an Mhaoir
Wisdom - Ó Céile
Wise - Uidheas
Wixted - Uicstéid
Wogan - Ugán
Wofe - Ó Mactíre
Wolfe - Ó Mactíre
Wolley - de Bhulbh
Woodlock - Uadlóg
Woods - Mac Conchoille
Woolahan - O hUallacháin
Wooley - de Bhulbh
Wordie - Mac Mhuireartaigh
Woulfe - de Bhulbh
Wrafter - Ó Reachtair
Mac Wray - Mac Raith
Wray - Ó Riabhaigh
Wren(n) - Mac Bhrain
Wright - Mac an tSaoir
Wrynn - Mac Bhrain
Wyer - Mac an Mhaoir
Wyndham - Ó Maolghaoithe
Wynn - Ó Gaoithín
Wyse - Uidheas
