ISO 14001 consists of the following parts:
- clauses 0 to 3 of the main part of the standard are clauses that describe the standard itself, so they are not mandatory for the implementation
- clauses 4 to 10 of the main part of the standard are mandatory because they set the requirements for an Environmental Management System.

Here are the non-mandatory clauses of ISO 14001:
- 0 Introduction - The introductory clause gives a general overview of the standard and its purpose and explains its compatibility with other ISO standards.
- 1 Scope—This section defines the scope of the standard, pointing out that it applies to all types of organizations.
- 2 Normative references – The second clause, Normative references,
- 3 Terms and definitions – Explains the main terminology.

Here are the mandatory clauses of ISO 14001:
- 4 Context of the organization—requires consideration of 'external and internal issues' (relevant factors from within the organization or outside it), interested parties and their requirements, and defining the EMS scope. This clause is important because it requires organizations to examine crucial inputs when defining and designing their EMS.
- 5 Leadership—This clause requires the definition of top management responsibilities, setting the general roles and responsibilities for the EMS, and defining the contents of the top-level Environmental Policy. This clause is important because it requires companies to define clear business goals for the environment and define their main responsibilities.
- 6 Planning - This clause defines environmental risks and aspects assessment, compliance obligations determination, and treatment requirements and sets the environmental objectives. This clause is important because it ensures the EMS effectively addresses risks and opportunities, setting a foundation for achieving intended environmental outcomes.
- 7 Support – This clause defines requirements for the availability of resources, competencies, awareness, communication, and control of documents and records. This clause is essential because it defines activities crucial for environmental success.
- 8 Operation - This clause encompasses the requirements for planning, implementing, and controlling the processes needed to achieve the required performance, avoid non-conformities, and prevent and respond to environmental emergencies. This clause is important because it defines how the EMS is used daily
- 9 Performance evaluation – This clause defines requirements for monitoring, measurement, compliance evaluation, analysis, evaluation, internal audit, and management review. This clause is important because it defines how companies must determine if their EMS is performing as expected.
- 10 Improvement – This clause defines nonconformities, corrections, corrective actions, and continual improvement requirements.