| # | Company name | Role | # of projects |
|---|---|---|---|
| 21 | Dawood Engineering | Engineering company | 1 |
| 22 | DBM Consulting Engineers | Engineering company | 1 |
| 23 | DDC Engineers Inc. | Engineering company | 1 |
| 24 | De Los Reyes Engineering, Inc. | Engineering company | 2 |
| 25 | Delta Airport Consultants Inc. | Engineering company | 1 |
| 26 | Denning Engineering | Engineering company | 1 |
| 27 | Dennis E Black Engineering Incorporated | Engineering company | 0 |
| 28 | DePouw Engineering LLC | Engineering company | 2 |
| 29 | Dewey & Associates | Engineering company | 2 |
| 30 | Digital Engineering | Engineering company | 2 |
| 31 | Dizayn Grup Ltd Sti | Engineering company | 1 |
| 32 | Dohn Associates | Engineering company | 1 |
| 33 | Doug Kepron | Engineering company | 0 |
| 34 | Douglas A Czerwinski | Engineering company | 1 |
| 35 | Dr. Lüchinger + Meyer Bauingenieure AG | Engineering company | 3 |
| 36 | Drash Consulting Engineers Inc. | Engineering company | 8 |
| 37 | Dunham Associates | Engineering company | 2 |
| 38 | Durrant Engineers Inc | Engineering company | 2 |