What is NAICS code 561621?

NAICS 561621 is the industry "Security Systems Services (except Locksmiths)" in the North American Industry Classification System, part of the Administrative and Support and Waste Management and Remediation Services sector (56).

What is the size standard for NAICS 561621?

The SBA sets a small business size standard for each NAICS code, either average annual receipts or number of employees. Check the current value for 561621 in the SBA table of size standards on sba.gov; it changes from time to time.

NAICS Code 561621: Security Systems Services (except Locksmiths)

NAICS code 561621 is the industry for security systems services (except locksmiths) in the Administrative and Support and Waste Management and Remediation Services sector. Agencies tag every federal contract with a NAICS code, so this is the code to list in your SAM.gov registration and to search for bids.

Government contracts under NAICS 561621

Federal agencies obligated $2.3B on contracts under NAICS 561621 from FY2024 to FY2026, including $711M in FY2026. The biggest buyers were the Department of Defense, the Department of Homeland Security, the Department of Justice. The largest contractors were M. C. Dean, Inc., Serco Inc, Paragon Systems Inc.

See the full breakdown: government security systems services (except locksmiths) contracts, who wins and who buys.

Open government bids for NAICS 561621

The newest open notices from SAM.gov. Bidding needs a free SAM.gov registration.

H263--ANTI-LIGATURE DOOR ALARM INSTALLATION SERVICESClosing soon
Veterans Affairs, Department of · Sources Sought · NAICS 561621 · Service-Disabled Veteran-Owned Small Business (SDVOSB) Set-Aside (FAR 19.14)
Posted Oct 30, 2026 · Responses due Nov 6, 2026
Lock, Key, and TRAKA Key Management Systems Maintenance and Support Services
Treasury, Department of the · Solicitation · NAICS 561621 · VA · Small Business Set Aside - Total
Posted Oct 30, 2026 · Responses due Nov 9, 2026
J012-- Fire Alarm Suppression Maintenance & Repair Services
Veterans Affairs, Department of · Combined Synopsis/Solicitation · NAICS 561621 · Service-Disabled Veteran-Owned Small Business (SDVOSB) Set-Aside (FAR 19.14)
Posted Oct 30, 2026 · Responses due Nov 12, 2026
J063--Security Access Control and Video Surveillance Systems Maintenance.Closing soon
Veterans Affairs, Department of · Sources Sought · NAICS 561621 · Small Business Set Aside - Total
Posted Oct 30, 2026 · Responses due Nov 5, 2026
Twenty-One Access-Control Door Panels and Enclosures and LenelS2 Onguard System Integration
Dept of Defense · Combined Synopsis/Solicitation · NAICS 561621 · FL · No Set aside used
Posted Oct 30, 2026 · Responses due Nov 12, 2026

See all 6 open bids under NAICS 561621

Small business size standard for NAICS 561621

To bid on small business set-aside contracts under NAICS 561621, your business must be small under the SBA size standard for this code, measured either by average annual receipts or by number of employees. The values are updated periodically, so check the current SBA table of size standards before you bid.

Other NAICS codes in 5616

How to choose the right NAICS code

Pick the 6-digit code that best describes what you sell. List it as your primary code in SAM.gov, and add other codes for related work. Agencies choose one NAICS code for each contract, so check the codes on past awards for the kind of work you do. Search all codes in the NAICS code lookup.

Related guides

Frequently asked questions

What is NAICS code 561621?: NAICS 561621 is the industry "Security Systems Services (except Locksmiths)" in the North American Industry Classification System, part of the Administrative and Support and Waste Management and Remediation Services sector (56).
What is the size standard for NAICS 561621?: The SBA sets a small business size standard for each NAICS code, either average annual receipts or number of employees. Check the current value for 561621 in the SBA table of size standards on sba.gov; it changes from time to time.
Are there government contracts for NAICS 561621?: Yes. Federal agencies obligated $2.3B on contracts under NAICS 561621 from FY2024 to FY2026, and 6 notices are open right now.