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Family law

Petitioner

The person who starts a court case by filing a petition, such as a petition for divorce.[1][2]

In more detail

California's courts use petitioner for the spouse who starts a divorce and note that, with a joint petition, both spouses are petitioners.[1][3] The federal courts' glossary defines a petition as a written request asking a court to act.[2]

Varies by state

Some states use plaintiff, especially in civil cases. Find your state’s rules.

Related terms

  • RespondentThe person who responds to a petition, such as the spouse who receives divorce papers.
  • PlaintiffThe person or organization that files a civil lawsuit.
  • ComplaintThe written statement a plaintiff files to start a civil case, saying why the court has jurisdiction, what the defendant allegedly did wrong, and what the plaintiff wants.

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Sources

The official documents this definition is based on, with the date we last read each one. Definitions are in our own words.

  1. Share your financial information (financial disclosure)selfhelp.courts.ca.govchecked ↩
  2. Glossary of Legal Termsuscourts.govchecked ↩
  3. Joint petition for divorce or legal separationselfhelp.courts.ca.govchecked ↩

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MediationList. (2026, October 28). Petitioner: Definition. https://mediationlist.com/glossary/petitioner/

APA 7th ed. A retrieval date is included only for pages whose content changes, such as maps, data and tools.