A supplier code of conduct sets out the minimum standards you expect from suppliers on labour and human rights, health and safety, the environment and business ethics. Base it on the UN Guiding Principles, the OECD Guidelines and the ILO core labour standards, keep it short, make it part of your purchasing terms, start with your most important and riskiest suppliers, and follow up with a questionnaire rather than audits for everyone.
What a supplier code of conduct is
A supplier code of conduct sets out the minimum standards a company expects from its suppliers on labour and human rights, health and safety, the environment and business ethics. It becomes part of the purchasing terms or the contract, so a supplier accepts it when it starts working for you. Some companies call it a supplier code, a responsible sourcing policy or a sustainable procurement charter.
Why companies need one
Customers ask for it. Large companies assess their suppliers’ sustainability, and EcoVadis scores sustainable procurement as one of its four themes. EU due diligence rules for the largest companies, which apply from July 2029 to EU companies with more than 5,000 employees and €1.5 billion turnover, and national laws such as Germany’s supply chain act, push expectations down the chain. And a code protects your own reputation if a supplier is found to break the rules.
What it covers
Most codes cover the same topics.
- Labour: no child labour or forced labour, freedom of association, reasonable working hours, fair wages and no discrimination.
- Health and safety: safe workplaces, training and protective equipment.
- Environment: compliance with environmental law, energy and emissions, waste, water and chemicals.
- Ethics: no corruption or bribery, fair competition, data protection and handling conflicts of interest.
- Management: passing the same standards on to subcontractors, a channel for workers to report problems, and your right to ask for evidence or audit.
The standards to build on
Do not invent your own principles. The UN Guiding Principles on Business and Human Rights, the OECD Guidelines for Multinational Enterprises on Responsible Business Conduct and the ILO Declaration on Fundamental Principles and Rights at Work are the references large customers and auditors recognise. The ILO declaration covers freedom of association, the elimination of forced labour and child labour, non-discrimination and, since 2022, a safe and healthy working environment.
Keep it proportionate
A code that asks a ten-person supplier for the same as a multinational will be signed and ignored. The amended EU reporting rules also limit what large reporting companies may ask of value-chain companies with fewer than 1,000 employees to what the voluntary standard (VSME) covers. Ask small suppliers for a signature and a short questionnaire, and keep audits for suppliers in high-risk countries or sectors.
Doing it in Greener Ahead
Greener Ahead does not audit suppliers. Carbon accounting in Greener Ahead lets you send suppliers a request: they answer in a portal of their own, in their own language, receive a score and certificate they can share, and their figures replace your spend estimates. It costs €1,495 per year with unlimited users, and you can try it free for 14 days without a card. Check the pricing page for current details.
What to ask, by supplier group
Match what you ask to the size of the supplier and the risk.
| Supplier group | What you ask | How you check |
|---|---|---|
| All suppliers | Accept the code as part of your purchasing terms | Signed acknowledgement or accepted terms |
| Main suppliers by spend | A short questionnaire on policies, emissions, safety and ethics | Answers with supporting documents |
| High-risk country or sector | The questionnaire plus certificates or audit reports | Document review, and an audit where needed |
| Suppliers with findings | An improvement plan with dates | A follow-up review |
Common mistakes
These make a code look good on paper and change nothing.
- A code so long that nobody reads it.
- Asking more of small suppliers than you can check yourself.
- No way for workers to report problems.
- Ending a contract at the first finding instead of agreeing improvements.
- Never checking whether the code is followed.
Sources and scope
- OECD: Guidelines for Multinational Enterprises on Responsible Business Conduct
- United Nations: Guiding Principles on Business and Human Rights
- ILO: Declaration on Fundamental Principles and Rights at Work
- EUR-Lex: Directive (EU) 2026/470 amending the sustainability reporting and due diligence directives
These resources explain a preparation workflow. Check your selected standard and recipient requirements before sharing your report.
Joost ThissenFounder
