Define: Zipper Clause

Zipper Clause
Zipper Clause
Quick Summary of Zipper Clause

A zipper clause is a provision in a contract that combines an integration clause and a no-oral modification clause. Its purpose is to prevent any claims or representations made outside of the written contract. For instance, if a company and an employee sign a contract with a zipper clause, the employee cannot later argue that the company made promises to them that were not included in the written contract. The zipper clause effectively “zips up” the contract, prohibiting the addition of any extra terms or promises. Another example could be a lease agreement between a landlord and a tenant. If the lease contains a zipper clause, the tenant cannot later assert that the landlord promised to make repairs or provide additional services that were not included in the written lease agreement. In summary, a zipper clause ensures that all terms and promises are included in the written contract, preventing any misunderstandings or disputes arising from oral agreements or representations.

What is the dictionary definition of Zipper Clause?
Dictionary Definition of Zipper Clause

A zipper clause is a contractual provision that states all agreed-upon terms are explicitly written in the contract, and no additional changes can be made unless they are also documented in the contract. This clause is referred to as a zipper clause because it effectively “zips up” the contract, preventing any further modifications.

Full Definition Of Zipper Clause

A zipper clause is a contractual provision commonly used in collective bargaining agreements (CBAs) between employers and trade unions. The primary purpose of a Zipper Clause is to stipulate that the terms and conditions outlined in the agreement are final and comprehensive, thereby waiving the right to negotiate any further issues until the contract expires. This legal overview will delve into the intricacies of Zipper Clauses, their legal implications, benefits, criticisms, and their role within the context of UK employment law.

Definition and Purpose

A zipper clause is a clause in a collective bargaining agreement that ensures no further negotiations on any topics covered in the agreement will take place during its term. It ‘zips up’ the agreement, meaning all discussions are closed and no additional claims can be made by either party until the agreement is renegotiated. This clause aims to provide both parties—employers and unions—with certainty and stability over the life of the contract.

Legal Context in the UK

In the UK, the legal framework surrounding collective bargaining is primarily governed by the Trade Union and Labour Relations (Consolidation) Act 1992 (TULRCA). While zipper clauses are more prevalent in the United States, they are not explicitly addressed in UK legislation. However, the principles underpinning Zipper Clauses can be aligned with the contractual nature of CBAs under UK law.

Components of a Zipper Clause

A typical Zipper Clause will include the following elements:

  1. Finality: Confirmation that the agreement is the full and final understanding between the parties.
  2. Waiver of Further Negotiations: A mutual waiver of the right to demand further negotiations on any issue covered in the agreement.
  3. Exclusions: Specific exclusions where renegotiation might still be permissible, such as unforeseen economic conditions or legislative changes,

Legal Implications

The inclusion of a Zipper Clause in a collective bargaining agreement has several legal implications:

  1. Enforceability: For a Zipper Clause to be enforceable, it must be clearly articulated within the agreement. Ambiguities can lead to legal disputes regarding the scope of the clause.
  2. Waiver of Rights: Both parties waive their statutory rights to further negotiation on covered issues, which could impact their ability to address unforeseen changes in circumstances.
  3. Dispute Resolution: In case of disputes over the interpretation of the Zipper Clause, the matter may be subject to arbitration or litigation, depending on the terms of the agreement.

Benefits of Zipper Clauses

  1. Stability and Predictability: By limiting the scope for renegotiation, Zipper Clauses provide stability and predictability, which can be beneficial for both employers and employees.
  2. Focus on Compliance: Employers and unions can focus on complying with the agreed terms without the distraction of ongoing negotiations.
  3. Efficient Use of Resources: Reducing the need for continuous negotiation conserves resources and time for both parties.

Criticisms of Zipper Clauses

  1. Inflexibility: The rigidity imposed by Zipper Clauses can be detrimental in dynamic and rapidly changing work environments.
  2. Employee Discontent: Employees may feel disenfranchised if they perceive that their concerns cannot be addressed until the agreement’s expiration.
  3. Legal Disputes: The enforcement of Zipper Clauses can lead to legal disputes, particularly if there is disagreement over the clause’s interpretation.

Case Law

In the UK, there is limited case law specifically addressing Zipper Clauses. However, analogous principles can be drawn from cases involving collective bargaining agreements and the waiver of statutory rights. For example, in the case of Wilsons & Clyde Coal Co Ltd v English [1938] AC 57, the House of Lords emphasised the importance of clear contractual terms, which is a critical consideration for the enforceability of Zipper Clauses.

Comparative Perspective

Zipper Clauses are more prominent in the United States, where they are supported by a robust body of case law. In contrast, the UK’s approach to collective bargaining agreements tends to focus more on the principle of good faith negotiations, as seen in cases like Ford Motor Co Ltd v AUEFW [1969] 2 QB 303. Despite this, the underlying principles of Zipper Clauses can be adapted within the UK legal framework, provided that the clauses are clearly drafted and mutually agreed upon.

Practical Considerations for Drafting Zipper Clauses

When drafting a Zipper Clause, it is essential to consider the following:

  1. Clarity and Precision: The language used must be clear and precise to avoid ambiguities that could lead to disputes.
  2. Scope: Define the scope of the clause explicitly, specifying which issues are covered and any exceptions.
  3. Mutual Agreement: Ensure that both parties fully understand and agree to the terms of the clause.
  4. Legal Review: Have the clause reviewed by legal professionals to ensure compliance with relevant laws and regulations.

Impact on Industrial Relations

Zipper Clauses can significantly impact industrial relations. On one hand, they can promote harmonious relations by providing a clear framework for the duration of the agreement. On the other hand, they can also lead to tension if employees feel their ability to address grievances is unduly restricted.


Zipper Clauses play a crucial role in collective bargaining agreements by providing finality and stability. While their use in the UK is less common than in the US, the principles behind these clauses can be effectively incorporated into UK CBAs. The key to their successful implementation lies in clear drafting, mutual understanding, and adherence to legal standards. By balancing the need for stability with the flexibility to address unforeseen issues, Zipper Clauses can contribute to more effective and harmonious industrial relations.

Zipper Clause FAQ'S

A zipper clause is a provision in a contract that states that the contract represents the entire agreement between the parties and that no other terms or conditions will be considered or included.

A zipper clause is included to prevent any additional terms or conditions from being added to the contract after it has been signed. It ensures that the contract remains complete and final.

Yes, a zipper clause can be modified or waived if both parties agree to the changes in writing. However, it is important to consult with legal counsel before making any modifications to ensure that the changes are legally valid.

If a contract does not have a zipper clause, it leaves room for additional terms or conditions to be added later, potentially leading to disputes or disagreements between the parties.

Yes, a zipper clause can be used in any type of contract, including employment agreements, lease agreements, purchase agreements, and more.

Yes, a zipper clause is generally enforceable in court as long as it is clear and unambiguous. However, the court will consider the specific circumstances and language of the contract when determining its enforceability.

Yes, a properly drafted zipper clause can prevent any oral agreements or understandings from being considered as part of the contract. It ensures that only the written terms of the contract are binding.

No, a zipper clause cannot be used to exclude or waive certain legal rights or protections that are provided by law. Any attempt to do so would likely be deemed unenforceable.

Yes, a zipper clause can be added to an existing contract through a written amendment or addendum. Both parties must agree to the addition of the zipper clause.

Yes, it is always advisable to consult with a lawyer before including a zipper clause or making any modifications to a contract. A lawyer can provide guidance and ensure that the clause is properly drafted to meet your specific needs and comply with applicable laws.

Related Phrases
No related content found.

This site contains general legal information but does not constitute professional legal advice for your particular situation. Persuing this glossary does not create an attorney-client or legal adviser relationship. If you have specific questions, please consult a qualified attorney licensed in your jurisdiction.

This glossary post was last updated: 9th June 2024.

Cite Term

To help you cite our definitions in your bibliography, here is the proper citation layout for the three major formatting styles, with all of the relevant information filled in.

  • Page URL:
  • Modern Language Association (MLA):Zipper Clause. DLS Solicitors. June 12 2024
  • Chicago Manual of Style (CMS):Zipper Clause. DLS Solicitors. (accessed: June 12 2024).
  • American Psychological Association (APA):Zipper Clause. Retrieved June 12 2024, from website:
Avatar of DLS Solicitors
DLS Solicitors : Family Law Solicitors

Our team of professionals are based in Alderley Edge, Cheshire. We offer clear, specialist legal advice in all matters relating to Family Law, Wills, Trusts, Probate, Lasting Power of Attorney and Court of Protection.

All author posts