Motion for Leave to File an Amicus Brief

When the motion for leave to file an amicus brief is used

Timing: generally no later than 7 days after the principal brief of the party being supported is filed. An amicus supporting neither side files within 7 days after the appellant's or petitioner's principal brief (Rule 29(a)(6)). The court may grant leave for later filing. Appeals follow a final judgment in most cases. The Federal Rules of Appellate Procedure govern this stage.

What the rule requires

• The motion must be accompanied by the proposed brief and state the movant's interest, why an amicus brief is desirable, and why the matters asserted are relevant to the disposition of the case (Rule 29(a)(3)).
• Unless the amicus is the United States or a state, the brief must state whether a party's counsel authored it in whole or in part, whether a party or its counsel contributed money to fund it, and whether any other person, other than the amicus, its members or its counsel, contributed money to fund it (Rule 29(a)(4)(E)).
• Amendments to Rule 29 have been proposed and are under review, so check the current version of the rule.
• The Federal Rules of Civil Procedure have no amicus rule. District courts decide such requests in their discretion, and some local rules address them.

In practice, read each requirement closely. Then check whether your court adds anything of its own. For example, many courts set page limits, formatting rules or a duty to confer with the other side first.

You can read the full text of Fed. R. App. P. 29 online. Also, the federal judiciary publishes the current rules and recent amendments.

The motion for leave to file an amicus brief in state court

State courts follow their own rules of procedure. Many states model their rules on the federal rules, so you will often find a similar motion for leave to file an amicus brief procedure. However, the name, the deadline and the required form can differ. Therefore, look up the matching rule in your state’s rules of civil procedure. Also read your court’s local rules. Our state procedures guide links to each state’s official rules.

Key terms

In addition, these terms come up often with this procedure:

• Amicus curiae: latin for "friend of the court." A person or organization that is not a party but files a brief to offer information or arguments to the court. Federal Rule of Appellate Procedure 29 governs amicus briefs in the federal courts of appeals.

Related procedures

Similarly, these procedures often come up alongside it:

• Opening Brief (Appellant's Brief): the appellant's main written argument in an appeal, explaining what the trial court got wrong and what the appellate court should do.
• Reply (Reply Brief or Reply to an Answer): the moving party's or appellant's answer to the other side's response or opposition, limited to the points raised there. In pleadings, a "reply to an answer" is allowed only if the court orders one.
• Motion to Intervene: a request by a nonparty to join an existing lawsuit.

Before you rely on this page

Always read the current rule yourself instead of relying on a summary. Next, check the local rules and the judge’s standing orders, since they often add steps. Then look for recent decisions from your court that apply the rule. Finally, talk to a licensed attorney about your situation. You can find one in our directory.

State court procedure for this filing

The federal rule above applies in federal court. In state court, the same filing is governed by that state's own rules of civil procedure, statutes and local court rules. Many states model their rules on the Federal Rules of Civil Procedure, so the requirements are often similar, but names, numbers, deadlines and forms can differ. Always use the version that applies to the court where your case is filed.

Find the rule in your state

In your state's rules, look for the rule on motion for leave to file an amicus brief. In states that number their rules like the federal rules, it is often the same rule number as the federal rule.