Tortious interference with contract—also known as intentional interference with contractual relations or business expectancy—is a civil claim or cause of action based on interference with a contract or a prospective contract that is about to be completed—by a person or entity who is not a party to the contract (third party).

A claim for tortious interference is based on the idea that the third party encouraged or induced one of the parties to the contract to breach the contract, causing damages to the nonbreaching party, who may sue the third party to recover those damages or losses. In some states there is a requirement that the interference be done maliciously or without justification.

Laws regarding claims for tortious interference with contract vary from state to state. Some states have broadened the protections against interference beyond situations where there is an existing contract and recognize claims for interference with prospective economic advantage or business relations.

But whether there is an existing contract or not, some instances of interference will not create legal liability and will be recognized as legitimate competitive activity, for example.

In Florida, tortious interference with a contract or business relationship is recognized as a legal cause of action. To establish a claim for tortious interference, the plaintiff must prove the existence of a contract or a valid business expectancy, the defendant's knowledge of the contract or expectancy, intentional and unjustified interference by the defendant causing a breach or termination of the relationship or expectancy, and damage to the plaintiff as a result. Florida law does not require that the interference be done with malice; however, the interference must be without justification. The courts in Florida distinguish between improper interference and actions that are considered legitimate competitive behavior. Therefore, not all interferences with contractual or business relations will result in legal liability, as some are protected under the concept of fair competition. An attorney can help individuals or businesses determine whether an action constitutes tortious interference and whether they have a valid claim under Florida law.