| # | Company name | Role | # of projects |
|---|---|---|---|
| 1 | L J Nodarse & Associates | Consultancy | 7 |
| 2 | L M Sweaney & Associates | Consultancy | 2 |
| 3 | L.A. Inc. | Consultancy | 2 |
| 4 | L.c Hohne Contractors Inc. | Consultancy | 0 |
| 5 | L.J. Harvey & Associates | Consultancy | 0 |
| 6 | L.n Storset & Associates, P.s | Consultancy | 0 |
| 7 | La Crosse Technical Consultants, Inc. | Consultancy | 8 |
| 8 | Laberge Engineering and Consulting | Consultancy | 0 |
| 9 | Laboratorio Nacional de la Construcción S.A. de C.V. | Consultancy | 16 |
| 10 | Laboratorios LIAC S.A. de C.V. | Consultancy | 3 |
| 11 | Laceco | Consultancy | 3 |
| 12 | Lakeside Blueprint | Consultancy | 0 |
| 13 | Lamphier & Associates | Consultancy | 2 |
| 14 | Lanc & Tully Engineering & Surveying PC | Consultancy | 0 |
| 15 | Lancaster Blueprinting | Consultancy | 1 |
| 16 | Lancaster Engineering | Consultancy | 1 |
| 17 | Land Development Services Inc | Consultancy | 0 |
| 18 | Land Plan Engineering Group | Consultancy | 1 |
| 19 | Land Planning Systems | Consultancy | 0 |
| 20 | Land Use Associates | Consultancy | 1 |