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 Wisconsin, consolidation of lawsuits is governed by the Wisconsin Statutes and the rules of civil procedure. According to Wis. Stat. § 805.05, when actions involving a common question of law or fact are pending before the court, it may order a joint hearing or trial of any or all the matters in issue in the actions; it may order all the actions consolidated; and it may make such orders concerning proceedings therein as may tend to avoid unnecessary costs or delay. This means that if there are multiple lawsuits with the same or similar parties, legal issues, and factual issues, a court in Wisconsin has the authority to consolidate these cases to streamline the process and reduce redundancy. The decision to consolidate is at the discretion of the court and is typically done to promote efficiency and fairness in the judicial process. If the cases are in different courts but within the same jurisdiction, a transfer may occur to consolidate them in one court. Federal courts have a similar mechanism under the Federal Rules of Civil Procedure, specifically Rule 42(a), which allows for consolidation when cases involve common questions of law or fact.