A complaint where the plaintiff (or, in limited cases, the plaintiff's counsel) swears to the allegations, demonstrating to a court that the plaintiff has investigated the charges against the defendant and found them to be of substance. In many jurisdictions, a complaint does not need to be verified unless a rule or statute specifically states otherwise. For example, under Federal Rule of Civil Procedure 23.1, the complaint in a shareholder derivative action must be verified (see Practice Note, Shareholder Derivative Litigation: Overview).

Typically, a plaintiff verifies a complaint by attaching a page at the end containing a statement made under oath that:

For model verified complaints, see standard documents: