What is Forum Shopping?

Legal Definition
Colloquially, forum shopping is the practice adopted by some litigants of having their legal case heard in the court thought most likely to provide a favorable judgment. Some jurisdictions have, for example, become known as "plaintiff-friendly" and so have attracted litigation even when there is little or no connection between the legal issues and the jurisdiction in which they are to be litigated.

Examples include the attraction of foreign litigants to the United States due to its expansive acceptance of personal jurisdiction and favorable litigation climate, and the United Kingdom for its stricter defamation laws and generous divorce settlements.

The term has become adopted in a wider context for the activity of repeatedly seeking a venue or willing listener for a concern, complaint or action, until one is found.
-- Wikipedia
Legal Definition
When multiple courts have concurrent jurisdiction over a plaintiff's claims, the plaintiff may forum shop, or choose the court that will treat his or her claims most favorably.

In the United States, forum shopping most typically occurs when state and federal courts have concurrent jurisdiction over a claim. State and federal courts have different procedural rules and, in some cases, also use different substantive law. See choice of law. Plaintiffs can use this to their advantage. For example, a plaintiff suing a large corporate defendant might sue in state court, predicting that a local jury would be more sympathetic than a federal jury. Alternatively, a plaintiff might prefer one jurisdiction due to a quirk of its procedural rules or due to its choice of law rule. See state procedural laws; Federal Rules of Civil Procedure.

Sometimes, plaintiffs deliberately structure their state law claims against out-of-state defendants to prevent the out-of-state defendants from removing the case to federal court, which might otherwise have diversity jurisdiction under 28 U.S.C. ยง 1332. For example, a plaintiff suing a major retailer might sue both the national parent company and its local store. By joining the in-state defendant, the plaintiff prevents federal courts from exercising diversity jurisdiction over the case for lack of complete diversity.

When forum shopping, plaintiffs are not limited to choosing between courts of different states, or state court and federal court. Sometimes, plaintiffs may be able to forum shop between courts in different countries. For a Supreme Court cases involving international forum shopping, see Ruhrgas AG v. Marathon Oil Co., 526 U.S. 574 (1999).

Courts discourage forum shopping. See forum non conveniens. In the United States, courts are particuarly concerned about forum shopping between state and federal courts located in the same state.

See Civil Procedure.