Yes, the Ethics Rules Do Apply to Mediators! New ABA Formal Opinion 518 Tells How

We know that the ethical rules apply when a lawyer acts as advisor, advocate, negotiator, intermediary between clients, spokesperson for a client, or evaluator. But what about when a lawyer serves as a mediator - what ethical rules apply? ABA Model Rule of Professional Conduct 2.4 specifically governs the conduct of third-party neutrals. It defines a third-party neutral as a lawyer who assists two or more persons – who are not the lawyer’s clients – to reach resolution of a dispute.

Model Rule 2.4(b) provides that a lawyer-mediator must advise unrepresented parties that he does not represent them and also requires the lawyer-mediator to explain the difference in his role as third party neutral and the role of a lawyer representing a client in mediation, when the lawyer knows that the parties do not understand the mediation process.

On October 15, 2025, the ABA released Formal Opinion 518 which provides guidance on the lawyer’s duty when acting as a third-party neutral:

• Clarify Mediator's Role: Lawyer-mediators must inform all unrepresented parties that they do not represent any of them and must explain the difference between the mediator's neutral role and an advocate's role as a lawyer. Sophisticated parties may require minimal clarification, while first-time mediation participants may need more in-depth explanation.

• Be Truthful: Lawyer-mediators must avoid puffery. Parties expect a mediator to be neutral and truthful - even minor exaggerations can be considered misleading and potentially violate Rule 8.4(c), which prohibits conduct involving dishonesty, fraud, deceit or misrepresentation.

• Provide Legal Information, Not Legal Advice: Mediators may provide legal information, such as how a court might rule on an issue, or explaining how courts generally evaluate damages or interpret contractual provisions, but must avoid giving legal advice, like telling a party a settlement is in their "best interest". Providing advice risks inadvertently forming an attorney-client relationship, which would compromise the mediator's neutrality. Unlike an attorney advocate, whose duty is to optimize outcomes, the mediator’s mandate is dispute resolution.

• Be Transparent When Relaying Party Statements: A mediator can relay a party's statement (even if it's puffery) but must make clear the origin of the statement and must not give it personal credence if the mediator knows it to be false. For example, it is unethical for a mediator to say "this is the best offer the opposing party will make" if it is untrue. 

A mediator’s effectiveness in dispute resolution comes from her credibility, which starts with perceived neutrality, not from advocacy tactics. Lawyers acting as mediators must adhere to even higher standards of truthfulness than when they act as advocates.

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About the Author

Sharon Stuart, President & Claims Counsel

Attorneys Insurance Mutual of the South

Sharon D. Stuart devotes her practice to civil trial work and arbitration, leads the way for our insurance company, and advises on numerous boards, committees, and associations.