| O'Brien Street, Kanturk | — | 5 |
| O'Briens Terrace, Midleton | — | 5 |
| O'Connell Avenue, Turners Cross | €299,999 | 16 |
| O'Connell Crescent, Turners Cross | €300,000 | 8 |
| O'Connell Street, Blackpool | — | 7 |
| O'Mahony Avenue, Bandon | — | 12 |
| O'Neill Crowley Terrace, Mitchelstown | — | 5 |
| O'Sullivans Place, Mallow | — | 6 |
| Oak Avenue, Bridewood | — | 5 |
| Oak Avenue, Classes Lake | — | 8 |
| Oak Brook, Tanyard Wood | €210,000 | 10 |
| Oak Close, Gleann Fia | €555,066 | 9 |
| Oak Dr, Brindle Hill | — | 7 |
| Oak Dr, Classis Lake | — | 7 |
| Oak Drive, Castle Heights | — | 6 |
| Oak Drive, Castleheights | — | 16 |
| Oak Drive, Rushbrooke Links | €270,000 | 26 |
| Oak Lawn, Tanyard Wood | €213,000 | 8 |
| Oak Park, Castleredmond | — | 16 |
| Oakbrook, Castlelake | €278,500 | 23 |
| Oakdene, Herons Wood | €445,000 | 20 |
| Oakdene, Skehard Rd | — | 6 |
| Oakfield Avenue, Glanmire | — | 7 |
| Oakfield Close, Glanmire | — | 7 |
| Oakfield Court, Glanmire | €380,000 | 10 |
| oakfield drive, glanmire | — | 15 |
| Oakfield Green, Glanmire | — | 8 |
| Oakfield Lawn, Ballinlough | — | 7 |
| Oakfield View, Glanmire | — | 14 |
| Oakhill, Sweetfield | — | 5 |
| Oakhill, Youghal | €225,563 | 25 |
| Oaklands, Ballincollig | — | 9 |
| Oaklands, White Oaks Ferney Road | — | 5 |
| Oaklawn, Bandon | — | 8 |
| Oakmount, Tower | €355,000 | 29 |
| Oakpark, Ballyhooly Rd | — | 5 |
| Oakridge, Castleheights | — | 8 |
| Oakridge, Dun an Oir | €220,000 | 17 |
| Oakridge, Meadowlands | €249,000 | 13 |
| Oakview, Douglas | — | 5 |
| Oakwood, Macroom | €250,000 | 27 |
| Ocean Drive, Kinsale Manor | — | 5 |
| Ocean Drive Road, Kinsale Manor | — | 22 |
| Oconnor Ville, Tower St | — | 5 |
| Odonovan Place, Cobh | — | 8 |
| Old Avenue, Glanmire | — | 16 |
| Old Avenue, Riverstown | — | 9 |
| Old Barrack Rd, Bantry | €135,000 | 9 |
| Old Blackrock Rd, Blackrock Rd | €350,000 | 10 |
| Old Chapel Lane, Clonakilty | — | 8 |
| Old Cliffe, Skehard Rd | — | 6 |
| Old Cork Rd, Midleton | — | 11 |
| Old Course, Mallow | — | 7 |
| Old Court, Greenfields | — | 12 |
| Old Friary Place, Shandon Street | €320,000 | 7 |
| Old Garden, Shanagarry | — | 5 |
| Old Head View, Kinsale Manor | — | 21 |
| Old Mills, Browns Mills | €425,000 | 5 |
| Old Quarry, Ballincollig | — | 8 |
| Old Quarry, Coolroe | — | 10 |
| Old Quarter, Ballincollig | — | 5 |
| Old Shambles Lane, Mallow | €174,458 | 7 |
| Old Waterpark, Carrigaline | — | 9 |
| Old Youghal Rd, Dillons Cross | €195,000 | 15 |
| Old Youghal Rd, Mayfield | €157,500 | 11 |
| Old Youghal Road, Cork City | €70,000 | 5 |
| Oldcastletown, Kildorrery | — | 6 |
| Oldcourt, Greenfields | €405,000 | 22 |
| Oliver Plunkett Hill, Fermoy | €139,500 | 18 |
| Oliver Plunkett Street, Bandon | €253,000 | 23 |
| Omahoney Ave, Bandon | €161,750 | 9 |
| Oneills Place, Cobh | — | 6 |
| Orchard Avenue, Castleredmond | €377,500 | 22 |
| Orchard Close, Ballincurrig Park | — | 6 |
| Orchard Court, Blackpool | €140,000 | 55 |
| Orchard Court, Orchard Road | €274,000 | 18 |
| Orchard Court, Rocky Rd | — | 7 |
| Orchard Court, Victoria Cross | — | 6 |
| Orchard Gardens, Shanagarry | — | 7 |
| Orchard Heights, Charleville | €230,000 | 62 |
| Orchard Heights, Rathgoggin Middle | — | 7 |
| Orchard Lane, Aherla | €272,000 | 9 |
| Orchard Manor, Glanmire | — | 5 |
| Orchard Manor, Riverstown | — | 9 |
| Orchard Manor, Shanagarry | — | 12 |
| Orchard Rise, Carrigaline | — | 9 |
| Orchard View, Heathfield | €376,154 | 12 |
| Orchid Grove, Abbey Fort | €436,123 | 23 |
| Orchid Grove, Abbeyfort | — | 16 |
| Orilia Terrace, Cobh | — | 8 |
| Orrery Road, Gurranabraher | €233,926 | 15 |
| Owenabue Dr, Ballea Rd | — | 5 |
| Owentaraglen, River Valley | — | 10 |
| Owentaraglen, Rivervalley | — | 7 |
| Owentarglen, River Valley | — | 9 |
| The Oak, Water Rock Manor | €409,691 | 25 |
| The Oaks, Bellevue | €395,760 | 21 |
| The Oaks, Blossom Hill | €344,383 | 14 |
| The Oaks, Bridgemount | — | 5 |
| The Oaks, Cois Maigh | €318,943 | 29 |
| The Oaks, Maryborough Ridge | €339,000 | 62 |
| The Old Dairy, Ballinacurra | €302,500 | 10 |
| The Old Mill, Carrigaline | — | 5 |
| The Olde Mills, Garyowen | — | 6 |
| The Orchard, Bishops Island | — | 5 |
| The Orchard, Blossom Hill | €360,617 | 20 |
| The Orchard, Blossomhill | €358,975 | 5 |
| The Orchard, Carleton | €418,502 | 25 |
| The Orchard, Chapel Hill | — | 11 |
| The Orchard, Chapel St | — | 7 |
| The Orchard, Clancy Terrace | €200,000 | 11 |
| The Orchard, College Manor | — | 11 |
| The Orchard, Crosshaven | — | 11 |
| The Orchard, Fairy Hill | — | 9 |
| The Orchard, Gleann Ull | — | 6 |
| The Orchard, Heathfield | €471,365 | 21 |
| The Orchard, Macroom | — | 5 |
| The Orchard, Summerhill | — | 8 |
| The Orchard, Watergrasshill | €295,154 | 46 |
| The Orchard, Woodville | — | 5 |
| The Orchards, Ballinacubby | — | 5 |
| The Orchards, Ballincubby | €320,000 | 10 |
| The Orchards, Ballynacubby | — | 7 |
| The Orchards, Castle Rock | — | 5 |
| The Orchards, Glasheen Rd | — | 5 |
| The Orchards, Herons Wood | — | 16 |
| The Orchards, Inchigaggin Lane | — | 6 |
| The Orchards, kinsale | €325,000 | 27 |
| The Orchards, Montenotte | — | 5 |
| The Oval, Eyeries | €234,536 | 11 |
| The Ovals, Rochestown Rd | — | 6 |