When parties to a contract make promises to perform their obligations, and one party reasonably relies on the other party’s promise—but the party making the promise fails to perform, causing harm or loss to the party who relied on the promise—the party who relied on the promise to perform is said to have relied to its detriment.

This legal concept is called detrimental reliance. Detrimental reliance may serve as a substitute for consideration, and make an otherwise unenforceable contract enforceable.

Thus, detrimental reliance is a legal concept based on fairness (known as equity or equitable), and is equivalent to contractual promissory estoppel (due to the other party’s reliance, the party who did not keep its promise is prohibited from challenging the enforceability of its promise).

Detrimental reliance is not a separate tort cause of action.

In Rhode Island, the legal concept of detrimental reliance, also known as promissory estoppel, is recognized and can be used to enforce a contract that may otherwise lack consideration and be unenforceable. Detrimental reliance occurs when one party makes a promise that the other party relies on to their detriment. If the promising party fails to fulfill their promise, and the other party has suffered harm due to their reliance on that promise, the harmed party may invoke detrimental reliance. This doctrine is grounded in principles of fairness and equity, aiming to prevent injustice by prohibiting the party who made the promise from arguing against the enforceability of their promise. While detrimental reliance is not a separate tort, it is an equitable remedy that can be used to enforce a contract in situations where one party has acted in reliance on the other's promise, and the reliance was reasonable and foreseeable. Rhode Island courts will consider factors such as the reasonableness of the reliance and the foreseeability of the harm when determining whether to apply promissory estoppel.