What Is a C3PAO and Why Does It Matter?

A C3PAO is a Certified Third-Party Assessment Organization. They’re accredited by the Cyber AB to perform official CMMC Level 2 assessments. If you handle Controlled Unclassified Information (CUI), your certification will ultimately pass through one of these organizations.

Only C3PAOs can perform Level 2 assessments

For Level 2, self-attestation isn’t enough. Under DFARS 252.204-7021, the Department of Defense requires a formal assessment by a Cyber AB-authorized C3PAO. Anyone else offering to “certify” you is either misinformed or misrepresenting what they can do.

Why they can’t also be your consultant

Assessment and preparation are separated by design to prevent conflicts of interest. That’s why RPOs (Registered Provider Organizations) exist to help you get ready, while C3PAOs test your readiness. If a firm offers both, it’s a red flag.

How to verify a C3PAO is legitimate

Go to the Cyber AB Marketplace and filter by C3PAO status.
Check that the organization is listed as Authorized (not just Candidate).
Confirm the listing shows current status and contact details that match what the vendor gave you.

What the assessment process looks like

Readiness review. The C3PAO validates scope and documentation against NIST SP 800-171.
On-site / remote fieldwork. Interviews, evidence collection, control testing.
Finding resolution. You address any deficiencies; the assessor reviews remediation.
Final decision. Pass/conditional pass and issuance of the certification report into CMMC eMASS.

How to choose the right C3PAO

Size fit. Do they regularly assess companies in your employee and revenue band?
Industry experience. Experience with manufacturing vs. software vs. engineering firms matters.
Current capacity. Many C3PAOs book months out. Ask about next available windows.

Red flags

Promises to “certify you for $5k” or “in two weeks.” Level 2 assessments don’t work that way.
They avoid providing their Cyber AB Marketplace listing.
They also sell remediation/consulting services directly.

For a detailed checklist of questions to ask any C3PAO or RPO, see How to Choose the Right CMMC Consultant.

We work with vetted C3PAOs. Let us match you.

We maintain active relationships with authorized C3PAOs across industries and company sizes. We know their schedules, strengths, and pricing models. Tell us your situation and we’ll recommend the right fit. Check your CMMC readiness first → or see what certification costs.