Consolidation of lawsuits may be ordered by a court when two or more lawsuits involving the same or similar parties (plaintiff and defendant), legal issues, and factual issues are pending in the same court or in different courts in the same jurisdiction (state court system or federal court system). If the lawsuits are pending in different courts one case may be transferred to the other court, and the cases consolidated there.

Laws and rules regarding the consolidation—or transfer and consolidation—of lawsuits vary from state to state and in the federal court system.

In Pennsylvania, courts have the authority to consolidate lawsuits when they involve common questions of law or fact to promote efficiency and avoid inconsistent judgments. This is governed by the Pennsylvania Rules of Civil Procedure, specifically Rule 213, which allows for consolidation or coordination of cases by the court's order. The decision to consolidate is at the discretion of the court and is typically considered when the actions involve the same parties, are related to the same transactions or events, and have similar legal and factual issues. If the cases are in different courts within the state, a transfer may be ordered to bring them into the same court for consolidation. The goal is to streamline the process, reduce litigation costs, and simplify the final resolution of the issues involved. Federal courts have a similar mechanism under the Federal Rules of Civil Procedure, Rule 42(a), which allows for consolidation when cases involve common questions of law or fact. The decision to consolidate in federal court is also at the discretion of the judge. It's important for parties considering consolidation to consult with an attorney to understand the implications and the process specific to their situation.