Third-Party Assessment Organization (3PAO)

Anyone can run an audit; only an accredited firm can produce assessment results FedRAMP accepts. 3PAOs earn that standing through a formal accreditation process that examines assessor qualifications, methodology, and quality management, and they keep it only through ongoing conformance. The roster of accredited firms is public, and cloud providers select and pay their own assessor from it — independence comes from the accreditation and the testing standards, not from government assignment.

The 3PAO writes the security assessment plan, tests every control the System Security Plan (SSP) claims, runs or validates penetration testing and vulnerability scanning, and delivers a security assessment report with a recommendation. Findings feed the remediation register — the Plan of Action and Milestones (POA&M) — and the package then goes to the authorizing official who decides the Authority to Operate (ATO). The relationship recurs, too: annual assessments continue for as long as the authorization lives. Program mechanics and timelines are covered on our FedRAMP framework page.

The near-identical acronyms cause constant confusion, and the distinction is worth being pedantic about. A 3PAO assesses cloud service offerings for FedRAMP, so federal agencies can buy those services. A CMMC Third-Party Assessment Organization (C3PAO) assesses defense contractors under the Cybersecurity Maturity Model Certification (CMMC) — a different program with a different accreditation body, different baselines, and a different certificate. A firm can hold both accreditations, but the engagements never interchange: passing one buys you nothing in the other regime.