Enterprise procurement teams ask for ISO 27001. US customers want a SOC 2 report. EU users trigger GDPR obligations. If you are a growing SaaS company, you will encounter all three — sometimes in the same security questionnaire. The confusion is understandable: they overlap significantly, use different language for similar concepts, and are governed by completely different bodies. Here is how they actually relate to each other.
Three Frameworks — At a Glance
| ISO 27001 | SOC 2 | GDPR | |
|---|---|---|---|
| What it is | International standard | AICPA attestation framework | EU regulation (law) |
| Nature | Certification (pass/fail) | Attestation report (opinion) | Legal requirement |
| Issued by | Accredited certification body | Licensed CPA firm | N/A — enforced by DPAs |
| Geography | Global — 160+ countries | Primarily US market | EU/EEA data subjects worldwide |
| Scope | Information security management | Trust Service Criteria (security, availability, etc.) | Personal data of EU residents |
| Validity | 3 years + annual surveillance | Type I: point-in-time; Type II: 6-12 month window | Ongoing — no expiry |
| Cost (typical) | Rs 8-25 lakhs first year | Rs 10-30 lakhs first year | No certification cost — compliance investment varies |
| Penalty for non-compliance | Loss of certification | Loss of report / client trust | Up to EUR 20M or 4% global turnover |
What Each Actually Is
ISO 27001 — A Certification
ISO 27001 is an international standard for Information Security Management Systems (ISMS). An accredited certification body audits your security management system in two stages (documentation review + operational verification). If you pass, you receive a certificate valid for three years, with annual surveillance audits. It tells the world: "This organisation has a systematic, audited security management programme."
SOC 2 — An Attestation Report
SOC 2 is an attestation framework developed by the AICPA (American Institute of Certified Public Accountants). A licensed CPA firm evaluates your controls against five Trust Service Criteria: security, availability, processing integrity, confidentiality, and privacy. The output is a report — not a certificate. Type I evaluates controls at a point in time; Type II evaluates them over a period (typically 6-12 months). It tells US enterprise buyers: "An independent auditor has tested our controls and issued an opinion."
GDPR — A Law
GDPR is the EU General Data Protection Regulation — a legally binding law, not a voluntary standard. It defines what rights individuals have over their personal data and what obligations organisations must meet. There is no GDPR "certification" to achieve. Compliance is an ongoing operational state enforced by Data Protection Authorities with the power to issue fines. For the full GDPR guide, see our GDPR Explained for Startups.
Detailed Comparison — What Each Requires
| Requirement | ISO 27001 | SOC 2 | GDPR |
|---|---|---|---|
| Risk assessment | Mandatory — formal methodology | Expected in Security criteria | Required for high-risk processing (DPIA) |
| Access controls | Annex A controls | Security criterion | Required under Article 32 |
| Incident response | Annex A.16 — incident management | Required under Security | 72-hour breach notification to DPA |
| Vendor management | Annex A.15 — supplier relationships | Required under Common Criteria | Article 28 — processor obligations |
| Encryption | Annex A.10 — cryptography | Expected under Confidentiality | Required under Article 32 (appropriate measures) |
| Data retention | Annex A controls reference | Addressed under Processing Integrity | Storage limitation principle — Article 5(1)(e) |
| User rights (access, deletion) | Not directly addressed | Privacy criterion covers some | Core requirement — 8 enforceable rights |
| Consent management | Not addressed | Privacy criterion | Core requirement — Article 6-7 |
| Data portability | Not addressed | Not addressed | Article 20 — right to portability |
| Internal audit | Mandatory — Clause 9.2 | Expected (part of monitoring) | Not explicitly required but evidence of accountability |
| Management review | Mandatory — Clause 9.3 | Board/management oversight expected | Not explicitly required |
| Continuous improvement | Mandatory — Clause 10 | Expected | Ongoing compliance obligation |
Where They Overlap
The good news: roughly 60-70% of controls overlap across ISO 27001 and SOC 2. If you implement one thoroughly, you have done the majority of the work for the other. The overlapping areas include:
- Risk assessment and risk treatment processes
- Access control policies and identity management
- Incident response and breach management
- Change management and system development lifecycle
- Vendor/supplier security management
- Business continuity and disaster recovery
- Security awareness training
- Logging, monitoring, and alerting
GDPR overlaps with both on security controls (Article 32 maps closely to ISO 27001 Annex A and SOC 2 Security criterion) but adds an entirely separate layer of privacy-specific requirements — consent, data subject rights, DPIAs, breach notification timelines — that neither ISO 27001 nor SOC 2 fully address.
ISO 27001 and SOC 2 are security frameworks. GDPR is a privacy law. Security is a prerequisite for privacy, but it is not sufficient. You can be fully ISO 27001 certified and SOC 2 attested and still be non-compliant with GDPR if you have not addressed consent, data subject rights, and lawful basis for processing.
Which Should You Pursue First?
| Your Situation | Recommendation |
|---|---|
| Selling to US enterprise customers | SOC 2 Type II first — it is the primary US procurement requirement |
| Selling to European or international enterprise customers | ISO 27001 first — it is the global standard recognised in 160+ countries |
| Selling to both US and international customers | ISO 27001 first, then SOC 2 — the control overlap means SOC 2 is cheaper after ISO 27001 |
| Processing personal data of EU residents | GDPR compliance is not optional — it is a legal obligation regardless of your other certifications |
| Indian company with DPDP Act obligations | ISO 27001 first (strongest evidence of reasonable safeguards), then layer ISO 27701 for privacy |
| Early-stage startup with limited budget | Start with ISO 27001 — it opens the most doors globally and the control foundation supports everything else |
Running Them Together
Most mature organisations end up with all three. The efficient approach is to build a single control library mapped to multiple frameworks rather than running parallel programmes:
- Build ISO 27001 as your foundation. It creates the ISMS structure, risk methodology, internal audit cycle, and management review that both SOC 2 and GDPR benefit from.
- Layer SOC 2 as a reporting mechanism. Most ISO 27001 controls map directly to SOC 2 Trust Service Criteria. The incremental work is primarily report preparation and CPA firm engagement.
- Layer GDPR as the privacy extension. ISO 27701 bridges ISO 27001 to GDPR by adding privacy-specific controls. Alternatively, build standalone GDPR controls on top of your ISMS.
- Use a GRC platform to maintain a single control library with multi-framework mapping — one evidence artefact satisfying three requirements simultaneously.
For the detailed ISO 27001 implementation path, see our ISO 27001 Explained for Startups guide.
Frequently Asked Questions
No. ISO 27001 is an international standard resulting in a certification valid for 3 years. SOC 2 is an AICPA attestation framework resulting in a report (Type I or Type II) issued by a CPA firm. They share roughly 60-70% control overlap but have different structures, geographies, and outputs.
It depends on your market. US enterprise buyers primarily ask for SOC 2. International buyers ask for ISO 27001. If you sell to both, you will eventually need both — but the control overlap means the second is significantly cheaper once the first is in place.
No. ISO 27001 addresses information security, not privacy. GDPR requires consent management, data subject rights, lawful basis documentation, breach notification within 72 hours, and DPIAs — none of which are fully covered by ISO 27001 alone. ISO 27701 bridges this gap by extending ISO 27001 with privacy-specific controls.
For Indian startups, ISO 27001 is typically cheaper (Rs 8-25 lakhs first year vs Rs 10-30 lakhs for SOC 2). ISO 27001 also has lower ongoing costs because surveillance audits are roughly 30-40% of the initial audit cost, whereas SOC 2 Type II requires a full re-engagement annually.
Yes, extensively. Roughly 60-70% of ISO 27001 Annex A controls map directly to SOC 2 Trust Service Criteria. If you build your ISO 27001 ISMS thoroughly, the incremental work for SOC 2 is primarily the report preparation and CPA firm engagement — not rebuilding controls from scratch.