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 Hawaii, the consolidation of lawsuits is governed by the Hawaii Rules of Civil Procedure (HRCP), specifically Rule 42(a), which allows for the consolidation of actions involving common questions of law or fact. The court may order a joint hearing or trial of any or all the matters in issue in the actions, consolidate the actions, or issue any other orders to avoid unnecessary costs or delay. This is applicable when cases are pending in the same court. If the cases are in different courts within the state, a transfer may be necessary before consolidation can occur. The decision to consolidate is at the discretion of the court and is based on the goal of judicial efficiency and the convenience of the parties. In the federal system, a similar rule exists under the Federal Rules of Civil Procedure (FRCP), Rule 42(a). The decision to transfer federal cases for consolidation is also subject to the federal venue statutes and the Judicial Panel on Multidistrict Litigation (JPML) if the cases are spread across multiple districts.