The Washington Business Journal annually ranks the 50 fastest growing companies located in the Washington, D.C., area. In 2009, 26 of the Fast 50 firms were based in Fairfax County.
| 2 | Global Telecom & Technology Inc |
| 3 | MicroTechnologies LLC |
| 6 | Carahsoft Technology Corp. |
| 7 | Criterion Systems Inc. |
| 9 | Accelera Solutions Inc. |
| 10 | iCore Inc. |
| 12 | VSE Corp. |
| 15 | Dominion Mechanical Contractors Inc. |
| 16 | TRS Consulting Inc. |
| 18 | mindShift Technologies Inc. |
| 19 | Excella Consulting Inc. |
| 21 | Apptix Inc. |
| 26 | Spectrum Inc. General Contracting |
| 27 | Versar Inc. |
| 28 | K12 Inc. |
| 29 | Abraxas Corp. |
| 35 | Customer Value Partners Inc. |
| 36 | NII Holdings Inc. |
| 37 | Intersections Inc. |
| 38 | NCI Information Systems Inc. |
| 40 | Celcite Management Solutions LLC |
| 42 | comScore Inc. |
| 45 | Knowledge Consulting Group Inc. |
| 46 | Guident Technologies Inc. |
| 47 | Truland Systems Corp. |
| 50 | Gladstone Capital Corp. |