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 Indiana, tortious interference with a contract occurs when a third party, who is not part of an existing contract, intentionally induces a contracting party to breach that contract, resulting in damages to the non-breaching party. The non-breaching party can then sue the third party for those damages. Indiana law requires the plaintiff to prove specific elements to establish a claim for tortious interference, including the existence of a valid and enforceable contract, the third party's knowledge of the contract, intentional inducement to breach the contract, the absence of justification, and damages resulting from the breach. Indiana also recognizes claims for interference with a business relationship or prospective economic advantage, even in the absence of an existing contract, provided that the interference was intentional and unjustified. However, not all interferences are actionable; acts of legitimate competition or business strategy that do not involve wrongful conduct may not constitute tortious interference under Indiana law.