When a person or business intentionally damages a business relationship or a contract you have with another business that caused or may cause economic harm. Tortious interference with a contract occurs when a third party intentionally damages the contractual between two parties.Both California contract law and tort law allow for legal action when a third party wrongfully interferes with a contract or ongoing business relationship. California courts have long recognized causes of action for tortious interference with contract and tortious interference with prospective economic advantage. If the defendant was a competitor regarding the business involved in the contract, his interference with the contract may not be improper. Tortious interference. When another business interferes with your business or contractual relationships causing economic damage. If a third party unfairly interferes with a business contract or relationship and causes damage, a tortious interference claim may be a viable option. Tortious interference often referred to as intentional interference with contractual relations, refers to the common law of torts. Tortious interference.