Businesses
- L and E Egan
- L O'Neill, solicitor
- L Rose and Company Limited
- Lacy's Hotel
- Lafayette Limited
- Laird Line Limited
- Lambert Brien and Company Limited
- Lambert Brothers
- Land Registry
- Lauder Brothers, photographers
- Laurence Keegan, gunsmith
- Laurence McNally, pawnbroker
- Law Library
- Lawlor, Briscoe and Company, house furnishers, auctioneers and valuers
- Lawrence and Company
- Lawrence and Son
- Lazarus and Rosenfeld Limited
- Leader Newspaper
- Leather Cloth Company Limited
- Leinster Building Works
- Leinster Regiment
- Lemon and Company Limited
- Leonard and Company
- Leverett and Frye Limited
- Lewers and Company
- Libby Limited
- Linenhall
- Linenhall Hotel
- Linnane and Company
- Liptons Limited, tea, wine, spirit and provision merchants
- Lisburn Street Dispensary
- Local Government Board
- London and Newcastle Tea Company
- London and North Western Railway Company
- Loreto Convent
- Lucania Cycle Works and Munitions Factory
- Lynch and Deering, solicitors
- Lysol Limited