An amicus (short for amicus curiae, Latin for “friend of the court,” and amici curiae is plural "friends of the court") is a person or organization that is not a party to a lawsuit but asks the court’s permission to file a brief to help the judges decide the case.

What an amicus brief does

Adds perspective: It gives the court information, expertise, or policy considerations the actual parties might not fully address.

Explains broader impact: It often shows how a ruling could affect an industry, a community, or the law in general—not just the two sides fighting.

Supports one side (usually): Although technically a “friend of the court,” most amici favor one party’s position and argue why that side should win.

Who can be an amicus?

Almost anyone with a legitimate interest or expertise can seek to file an amicus brief, including, but not limited to: trade associations and professional groups, civil rights or advocacy organizations, universities and legal scholars, government officials (like attorneys general), individuals with unique knowledge relevant to the case, individuals who will be impacted by the case

How it works in practice

The amicus must usually ask the court for permission (or get consent from the parties) before filing.

The brief must disclose who the amicus is, why they care about the case, and often whether a party helped pay for or write the brief.

The amicus cannot raise brand‑new issues that weren’t already presented to the lower courts; it must work within the existing case.

Simple analogy

Think of a trial or appeal as a debate between two sides. An amicus is like an expert witness who doesn’t testify live but instead hands the judge a short memo saying, “Here’s why this decision matters more broadly, and here’s some specialized knowledge you should consider.”

In short: an amicus is an outside “friend of the court” who files a brief to help the judges make a better‑informed decision, especially in cases with wide‑reaching legal or public‑policy consequences.