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 Maryland, the consolidation of lawsuits is governed by the Maryland Rules of Procedure, specifically Rule 2-503. This rule allows for the consolidation of actions when there are common questions of law or fact to promote convenience and efficiency. The court has the discretion to order consolidation if it determines that it would serve the interests of justice and judicial economy. This can occur when multiple lawsuits involving the same parties, legal issues, or factual circumstances are pending in the same court. If the cases are in different courts within the state, a transfer may be necessary before consolidation. The decision to consolidate is case-specific and considers factors such as the risk of inconsistent judgments and the potential for the reduction of litigation costs and time. Federal courts have a similar mechanism under Federal Rule of Civil Procedure 42(a), which allows for consolidation when actions involve a common question of law or fact. The decision to consolidate in either state or federal court is ultimately at the discretion of the court.