ISO 27001 vs SOC 2.
The comparison usually gets framed as a choice between two products, and it is not one. ISO 27001 is a certification, issued by a body that has itself been accredited. SOC 2 is an attestation: a licensed CPA firm examines your controls and signs an opinion. They are different instruments, they are read by different people, and the decision is almost never yours — it belongs to whoever put the requirement in front of you.
The useful question is therefore not which is stronger. It is which one the customer blocking your deal asked for, and whether the work you do for it also counts toward the other. Mostly it does.
The short answer.
Choose ISO 27001 if the requirement came from European, UK or Asia-Pacific procurement, from a tender, or from a supplier questionnaire with a certificate field. Choose SOC 2 if it came from a US enterprise security review. That single test resolves most cases, because in most cases somebody has already decided and the task is to find out what they decided.
If nothing is blocked yet and you sell to both, start collecting evidence now and pick later. A SOC 2 Type 2 covers an observation period, so the clock is the expensive part, and the access reviews, change records and incident history that fill it are the same records an ISO audit will ask to see.
Six differences that
change what you do.
Ordered by how early each one bites. The instrument and its issuer decide everything below them; the last two are the ones people discover late and expensively.
What the instrument is
- ISO 27001
- A certification against a management system standard. The auditable object is the management system itself: scope, risk assessment, Statement of Applicability, and the evidence that the system runs.
- SOC 2
- An attestation. A CPA firm examines controls against the Trust Services Criteria and issues an opinion. The opinion is the deliverable, and it is the practitioner's, not yours.
ISO asks whether you run a system for managing security. SOC 2 asks whether a set of controls was described fairly and operated as described. A company can pass either while a reader of the other would have questions.
Who issues it
- ISO 27001
- A certification body, which is itself accredited by a national accreditation body under the Global ACI mutual recognition arrangement. ISO writes the standard and certifies nobody.
- SOC 2
- A licensed CPA firm, under the AICPA's attestation standards. There is no accreditation layer above the firm in the ISO sense; the licence and the professional standards carry that weight.
Ask a certification body for its accreditation, and ask a CPA firm for its licence and peer review. An unaccredited ISO certificate and an audit-mill SOC 2 fail the same way: the artefact exists and means less than the buyer assumes.
What the artefact looks like
- ISO 27001
- A certificate, typically one page, naming the scope and the certification body. It is public, and most accreditation bodies run a register where anyone can verify it.
- SOC 2
- A report, often dozens of pages, containing the opinion, the system description and — in a Type 2 — the tests and their results. It is confidential and usually goes out under NDA.
This is the difference that drives the rest. An ISO certificate can sit on your website; a SOC 2 report cannot. Anything a prospect can check before contacting you, they will check.
What the period means
- ISO 27001
- A three-year certification cycle: an initial audit, then surveillance audits, then recertification. The certificate is current until it is withdrawn or expires.
- SOC 2
- Type 1 is a point in time. Type 2 covers a stated observation period, commonly three to twelve months, and says what happened during it. A report always ages.
A SOC 2 Type 2 leaves a gap between the period end and today, which buyers cover with a bridge letter. An ISO certificate has no equivalent gap but says far less about any particular day inside the cycle.
What you can read before you commit
- ISO 27001
- ISO/IEC 27001 and 27002 are sold, not published. Reading the requirements you are about to be audited against is a purchase.
- SOC 2
- The Trust Services Criteria and the AICPA's description of the SOC suite are published free. You can read the criteria before anyone quotes you a fee.
This asymmetry is why the page you are reading quotes the AICPA verbatim and only cites ISO. It is also why SOC 2 preparation advice is easier to check, and why bad ISO advice survives longer.
Who actually decides
- ISO 27001
- Usually EU, UK and APAC procurement, tenders, and anyone whose supplier questionnaire has a certificate field. Increasingly cited in European regulatory contexts as evidence of an established practice.
- SOC 2
- Usually US enterprise procurement and security review, where the report is read by a security team rather than filed by a procurement team.
Neither is better. The right question is not which framework is stronger but which one the customer blocking your deal has asked for, and that is a sales question you can answer this week.
From the bodies
that run each one.
The accreditation body on the ISO side changed on 1 January 2026: the International Accreditation Forum ceased operations and Global ACI took over the recognition arrangement. Comparison pages still naming the IAF as current are describing a body that no longer operates.
Accreditation is the independent evaluation of conformity assessment bodies against recognised standards to ensure their impartiality and competence
The ISO side has a layer the SOC 2 side does not: the body that certifies you is itself evaluated. Global ACI took this arrangement over from the International Accreditation Forum on 1 January 2026, so anything describing the IAF as current is out of date.
Established in 2011, SOC reports are examinations performed by CPAs in accordance with the AICPA’s Statements on Standards for Attestation Engagements to evaluate the controls over customer data that service organizations such as cloud providers or payroll processors have in place
An examination performed by CPAs, not a certification issued against a standard. That distinction is the whole of this page, stated by the institute that defines the report.
The 2017 Trust Services Criteria for Security, Availability, Processing Integrity, Confidentiality, and Privacy (With Revised Points of Focus — 2022) (2017 TSC) presents control criteria established by the AICPA’s Assurance Services Executive Committee (ASEC) for use in attestation or consulting engagements
Criteria for an engagement, published free. ISO/IEC 27001 is sold, which is why the requirements half of this comparison is cited rather than quoted.
Doing both is not
twice the work.
The evidence overlaps heavily
Access reviews, onboarding and offboarding, change management, vulnerability management, backups, incident handling and vendor oversight are collected once and read by both. The same access review satisfies an ISO Annex A control and a SOC 2 common criterion.
The documents do not
ISO wants a Statement of Applicability, a risk assessment method and management review records — artefacts of a management system, with no SOC 2 counterpart. SOC 2 wants a system description written to the AICPA's description criteria, which ISO does not ask for.
The order is usually decided for you
Do the one your blocked deal needs first. Where nothing is blocked, a Type 2 observation period is the long pole: starting evidence collection early costs nothing and shortens the report you can eventually sell against.
Sources
- AICPA & CIMA, 2017 Trust Services Criteria (With Revised Points of Focus — 2022)
- AICPA & CIMA, System and Organization Controls: SOC Suite of Services
- Journal of Accountancy, “Promises of ‘fast and easy’ threaten SOC credibility”, February 2026
- Global Accreditation Cooperation Incorporated (Global ACI), About Global ACI
- ISO/IEC 27001:2022, Information security management systems — Requirements
- ISO, Management system standards
The AICPA publishes its criteria, so the SOC 2 half is quoted. ISO/IEC 27001 is sold rather than published, so the ISO half is cited and nothing is quoted from the body of the standard. Last reviewed .