| # | Company | Employees |
|---|---|---|
| 1 |
Amentumamentum.com
Amentum is a global leader in engineering, project management, and solutions integration, specializing in modernizing critical missions worldwide with speed and confidence |
50,000 |
| 2 |
Booz Allen Hamiltonboozallen.com
Innovative technology consulting firm advancing critical missions through AI, cybersecurity, and engineering solutions, empowering clients to shape the future |
37,244 |
| 3 |
Leidosleidos.com
Global technology leader providing digital mission innovations and efficient technical services for government and commercial customers through a diverse, flexible work environment. |
37,171 |
| 4 | 36,645 | |
| 5 |
General Dynamics Information Technologygdit.com
Provides technology and professional services to U.S. government agencies, specializing in digital modernization, AI, cloud, cyber, and application development worldwide. |
26,598 |
| 6 |
CACI International Inccaci.com
providing advanced technology and expert services to address complex national security challenges for government and defense sectors |
22,223 |
| 7 |
Parsons Corporationparsons.com
A digitally enabled solutions provider creating future defense, intelligence, and critical infrastructure solutions with an agile and innovative approach |
20,710 |
| 8 |
Peratonperaton.com
A company at the forefront of solving global challenges with innovative solutions, prioritizing safety and security through fresh perspectives and talent |
18,000 |
| 9 |
MANTECHmantech.com
A dedicated company providing technology services to support national security, military welfare, community protection, and healthcare advancement for over 50 years |
10,459 |
| 10 |
General Dynamics Mission Systemsgdmissionsystems.com
A mission-critical C4ISR solutions provider developing technology for communication, data sharing, mine detection, and more across various domains |
9,815 |
| 11 |
Accenture Federal Servicesaccenture.com
The company brings advanced R&D, latest technologies, and human-centered design to the federal government to create lasting value and drive positive change |
9,719 |
| 12 | 9,164 | |
| 13 |
Mission Technologies, a division of HIIhii.com
The company's Mission Technologies division develops integrated solutions for military operations, including C5ISR, AI, cyberspace strategies, unmanned systems, and platform modernization |
5,049 |
| 14 |
ECSecstech.com
ECS provides advanced technology, science, and digital solutions to address cyber threats for customers in the public and private sectors |
3,996 |
| 15 | 3,917 | |
| 16 |
M.C. Dean, Inc.mcdean.com
Designing, building, and maintaining cyber-physical solutions for critical facilities, secure environments, infrastructure, and enterprises; specializing in electrical, security, telecommunications, and control systems |
3,845 |
| 17 |
GovCIOgovcio.com
Deliver IT solutions and services using Agile methods and innovation to optimize government operations and support citizen-focused missions. |
3,164 |
| 18 |
SRA, a CSRA company
A provider of information technology services that acquired CSRA Inc in 2018 and completed a combination with SRA International in 2015 |
2,492 |
| 19 |
ePlus inc.eplus.com
Leading provider of comprehensive IT solutions, including security, cloud services, data migration, data center management, collaboration, and networking expertise, driven by innovation and customer-centric focus |
2,071 |
| 20 | 2,001 | |
| 21 |
Agile Defenseagiledefense.com
Innovating IT solutions for US government agencies, transforming operations through a philosophy of listening, thinking, and innovation |
1,572 |
| 22 | 1,569 | |
| 23 |
Red Riverredriver.com
Provides technology integration services with expertise in security, networking, analytics, collaboration, mobility, and cloud solutions for businesses and government. |
1,527 |
| 24 |
QinetiQ USqinetiq.com
Innovative technology development for defense, security, and commercial markets with focus on Mission Operations, ISR, Cyber, Information Advantage, and Robotics |
1,474 |
| 25 |
Engility Corporationsaic.com
A premier technology integrator based in Reston, Virginia, providing information about SAIC through their linkedin page |
1,414 |
| 26 |
22nd Century Technologies Inc.tscti.com
Providing managed IT services and solutions including digital transformation, cloud migration, cybersecurity, application modernization, and workforce support for government agencies. |
1,392 |
| 27 | 1,386 | |
| 28 |
GuidePoint Securityguidepointsecurity.com
Elite team of certified experts providing holistic cybersecurity solutions, guiding organizations to make informed decisions, choose appropriate products, and optimize resources |
1,364 |
| 29 |
Noblisnoblis.org
A nonprofit organization providing scientific, technology, and strategy services to government and industry clients in national security, healthcare, and environmental sustainability |
1,313 |
| 30 |
HII Technical Solutions, a division of Huntington Ingalls Industriestsd.huntingtoningalls.com
The company specializes in mission technologies, offering a range of services and solutions Visit their new LinkedIn page for more information |
1,295 |
| 31 | 1,165 | |
| 32 | 983 | |
| 33 |
Everfoxeverfox.com
A leading provider of defense-grade cyber security solutions, specializing in cross domain, threat protection, and insider risk solutions for governments and enterprises |
760 |
| 34 |
By Light Professional IT Servicesbylight.com
Hardware and software engineering services provider for defense, civilian, and commercial sectors worldwide, offering reliable and cost-effective IT solutions |
731 |
| 35 |
L-3 National Security Solutionscaci.com
A company that was acquired by CACI International Inc on February 1, 2016, specializing in national security solutions Visit https://wwwlinkedincom/company/caci-international-inc |
729 |
| 36 |
Command Security Corporationprosegur.us
A security company in the US now part of Prosegur, specializing in guarding services Explore more at wwwprosegurus |
700 |
| 37 |
AMSEC LLC, A Subsidiary of Huntington Ingalls Industrieshii.com
A global company with over 35 locations providing maintenance, modernization, unmanned systems development, engineering, logistics, software development, and training solutions |
698 |
| 38 |
Two Six Technologiestwosixtech.com
Innovative company specializing in cyber, information operations, data science, electronic systems, and more to solve complex global challenges for various government agencies |
670 |
| 39 |
Telos Corporationtelos.com
Empowering and protecting organizations with continuous security assurance for individuals, systems, and information through cybersecurity, cloud, and enterprise security solutions. |
665 |
| 40 |
Alpha Omegaalphaomega.com
Alpha Omega specializes in providing mission-focused solutions in cybersecurity, data and AI, and digital modernization for national security, foreign affairs, and climate science |
613 |
| 41 |
UltraViolet Cyberuvcyber.com
Provides tech-enabled managed security services and cybersecurity expertise to Global 2000 companies and the Federal Government, offering integrated security capabilities. |
601 |
| 42 |
Core4cecore4ce.com
Mission-oriented company serving national security community by building, modernizing, and defending digital infrastructure with expertise in cyber operations, modernization, engineering, and analysis |
599 |
| 43 | 353 | |
| 44 | 292 | |
| 45 |
Zachary Piper Solutionszacharypiper.com
A technology services firm providing government contracting solutions for the Intelligence Community, specializing in cybersecurity, intelligence technologies, and national security objectives |
243 |
| 46 |
DirectViz Solutions, LLCdirectviz.com
This company provides strategic consulting, network support, cybersecurity, systems engineering, cloud computing, and innovative technology solutions to commercial and government clients |
228 |
| 47 |
AEgis, a BlueHalo Companybluehalo.com
Specializing in Space Superiority, Directed Energy, Missile Defense, C4ISR, Cyber, and Intelligence solutions, this company provides industry-leading mission capabilities |
228 |
| 48 |
TCB | 24/7 EXPERT IT Supporttcbinc.com
Innovative IT solutions provider specializing in managed services, network security, software development, consulting, and computer products for businesses since 1993 |
174 |
| 49 |
Criterion Systemscherokee-federal.com
A cybersecurity and IT services company providing cloud automation, solutions engineering, and IT infrastructure operations with a commitment to employees' success |
168 |
| 50 |
OCT Consulting LLCoctconsulting.com
An SBA-certified 8(a) small disadvantaged business offering professional services to federal government and commercial clients, led by experienced industry professionals |
63 |
| 51 | 52 | |
| 52 |
Data Machinesdatamachines.com
A data analytics company specializing in cloud architectures, solving complex problems in data analytics, DevSecOps, machine intelligence, and data science |
45 |
| 53 |
Elite Systems Inc.elitesystems.com
The company specializes in systems integration, cloud migration, software development, network and applications security, cyber security, RF benchmarking, wireless optimization, and IT staffing |
28 |
| 54 |
INSI Cloud Inc.insicloud.com
A leading IT solutions provider specializing in Business Operations, Cyber Security, AI, and ML solutions for government clients with top certifications |
28 |
| 55 |
WINTrio LLCwintrio.com
This company specializes in IT Modernization, Cyber Security, Cloud/DevSecOps, Software, and Support services, offering custom solutions to improve overall performance |
17 |
Turn this list into pipeline
Tamtam finds the decision-makers at every company on a list like this one, with verified emails, phone numbers and the buying signals that tell you when to reach out.
How this list is built
Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Oct 24, 2026.
More company lists in Virginia
- The largest companies in Virginia 2,503
- IT Services and IT Consulting companies in Virginia 398
- IT services companies in Virginia 253
- Aerospace and defence companies in Virginia 155
- Defense and Space Manufacturing companies in Virginia 120
- Hospitals and Health Care companies in Virginia 120
- Education providers in Virginia 118
- Consulting firms in Virginia 101
- Non-profit Organizations companies in Virginia 101
- Higher Education companies in Virginia 100
- Software Development companies in Virginia 97
- Retail chains in Virginia 95
- SaaS companies in Virginia 95
- Critical infrastructure operators in Virginia 90
- Financial services firms in Virginia 87
- Public sector organisations in Virginia 83
- Real Estate companies in Virginia 79
- Financial Services companies in Virginia 74
- Business Consulting and Services companies in Virginia 69
- Construction companies in Virginia 69
- Government Administration companies in Virginia 69
- AI companies in Virginia 63
- Healthcare providers in Virginia 63
- Manufacturers in Virginia 56
The same list elsewhere in United States
- Cybersecurity companies in the United States 670
- Cybersecurity companies in California 157
- Cybersecurity companies in New York State 76
- Cybersecurity companies in Texas 57
- Cybersecurity companies in Massachusetts 36
- Cybersecurity companies in Florida 34
- Cybersecurity companies in Maryland 27
- Cybersecurity companies in New York 65
- Cybersecurity companies in San Francisco 42