Businesses
- Kane and Company
- Kapp and Peterson Limited, tobacconists
- Kearney Brothers
- Keating and Keating, solicitors
- Kellner Partington Paper Pulp Company Limited
- Kelly Brothers Limited
- Kennedy and McSharry
- Khaki Tea and Supper Rooms
- Kildare Street Club
- Kilworth Hotel
- Kincaid and Matthews, land agents
- King's shop
- Kingstown [Dún Laoghaire] Harbour Commissioners
- Kodak
- Kops Brewery