| # | Company name | Role | # of projects |
|---|---|---|---|
| 981 | G C Mapping Service | Consultancy | 3 |
| 982 | G J Thelen & Associates | Consultancy | 0 |
| 983 | G M B Engineering Inc. | Consultancy | 1 |
| 984 | G.J. Sweeney Associates | Consultancy | 0 |
| 985 | G&W Engineers Inc. | Consultancy | 1 |
| 986 | G3 Quantity Surveying | Consultancy | 0 |
| 987 | Gabinete de Estudios Ambientales | Consultancy | 1 |
| 988 | Gabriele Development Services | Consultancy | 1 |
| 989 | Gaisiner Asher Engineering Consultants | Consultancy | 1 |
| 990 | GAKO AB | Consultancy | 10 |
| 991 | Galloway & Company | Consultancy | 0 |
| 992 | Galson Corporation | Consultancy | 1 |
| 993 | Gambert Engineering Consulting & Decoration | Consultancy | 1 |
| 994 | Gannett Fleming | Consultancy | 0 |
| 995 | Garden Reproductions | Consultancy | 0 |
| 996 | Garrett Engineering PC | Consultancy | 1 |
| 997 | Garrison Partners Consulting | Consultancy | 30 |
| 998 | Gartek Engineering Corp. | Consultancy | 8 |
| 999 | Gartner | Consultancy | 0 |
| 1,000 | Gary G Bruno | Consultancy | 2 |