| 00680WB | W Cooney Electronics | YES | YES | | YES | YES | YES | YES | YES | YES |
| 00223WB | W. B. Peat & Company Ltd | YES | YES | Peats | YES | YES | YES | YES | YES | YES |
| 01534W | Wacker Neuson Ltd | YES | NO | | N/A | N/A | N/A | N/A | N/A | YES |
| 00628W | Walker Technology Products Ltd | YES | NO | | YES | YES | YES | YES | YES | Reg-Pending |
| 01178WB | Walter Bourke & Son Ltd | YES | YES | | N/A | N/A | N/A | YES | YES | YES |
| 00523W | Waltons Music Limited | YES | NO | | YES | YES | YES | YES | YES | YES |
| 00263W | Waterford Stanley Ltd | YES | NO | | YES | YES | YES | YES | YES | YES |
| 01020W | Watermark Engineering Ltd | YES | NO | Watermark Coffee Technology | YES | YES | YES | YES | YES | Reg-Pending |
| 00132W | Waters Chromatography Ireland Ltd | YES | NO | | YES | YES | YES | YES | YES | YES |
| 00182W | Waters Technologies Ireland Limited | YES | NO | | YES | YES | YES | YES | YES | YES |
| 00287 | Watlow Electric Manufacturing Company | YES | NO | | YES | NO | NO | NO | NO | NO |
| 01590WB | Waveform Solutions Ltd | YES | YES | | NO | NO | NO | NO | Reg-Pending | NO |
| 00693WB | Weigh-Tech Limited | YES | YES | | YES | YES | YES | YES | YES | Reg-Pending |
| 00711WB | Weir & Sons | YES | YES | | YES | YES | YES | YES | YES | YES |
| 01603WB | Wella (U.K.) Ltd | YES | YES | Wella Ireland | N/A | N/A | N/A | N/A | N/A | YES |
| 00245WB | Wesco Electrical Ltd | YES | YES | | YES | YES | YES | YES | YES | YES |
| 01587WB | Westbourne I.T. Solutions Ltd | YES | YES | | N/A | N/A | N/A | N/A | Reg-Pending | Reg-Pending |
| 01232B | Westward Garage Ltd | NO | YES | Westward Scania | N/A | N/A | N/A | YES | YES | YES |
| 00069W | Whirlpool Ireland | YES | NO | | YES | YES | YES | YES | YES | YES |
| 01387W | Whitelight LED Ltd | YES | NO | | N/A | N/A | N/A | N/A | Reg-Pending | Reg-Pending |
| 00435W | Whitgale Limited | YES | NO | General Lighting | YES | YES | YES | YES | YES | YES |
| 01043W | Whitkil Limited | YES | NO | | YES | YES | YES | YES | YES | YES |
| 00086 | Wild About Water Ltd | YES | NO | | YES | YES | YES | NO | NO | N/A |
| 01519WB | William Reynolds and Sons Ltd | YES | YES | Reynolds of Raphoe | YES | YES | YES | YES | YES | YES |
| 00921W | Willie Duggan Lighting Ltd | YES | NO | | YES | YES | YES | YES | YES | YES |
| 00891W | Wincor Nixdorf Ltd | YES | NO | | YES | YES | YES | YES | YES | YES |
| 00683W | Wink Lighting Ltd | YES | NO | | YES | YES | YES | YES | YES | YES |
| 01283W | Winning Ways Ltd | YES | NO | | YES | YES | YES | YES | YES | YES |
| 01366WB | Wire-Lite Sensors Ltd | YES | YES | | N/A | N/A | N/A | YES | YES | Reg-Pending |
| 01544W | Wood Communications | YES | NO | | N/A | N/A | N/A | N/A | N/A | Reg-Pending |
| 00222WB | Woodie's D.I.Y. Ltd | YES | YES | | YES | YES | YES | YES | YES | YES |
| 01493WB | Workshop Supplies & Components | YES | YES | | NO | NO | NO | NO | Reg-Pending | Reg-Pending |
| 00353WB | Worth Data, Inc. | YES | YES | | YES | YES | YES | YES | YES | Reg-Pending |
| 00396WB | WP Diagnostics | YES | YES | | YES | YES | YES | YES | YES | Reg-Pending |
| 00835W | WRTL Exterior Lighting Ltd | YES | NO | | N/A | YES | YES | YES | YES | YES |
| 01144WB | WT Burden Ltd | YES | YES | | YES | YES | YES | YES | YES | Reg-Pending |
| 00896WB | Wurth (Ireland) Ltd | YES | YES | | YES | YES | YES | YES | YES | YES |