The doctrine of unjust enrichment applies the principles of restitution to disputes that are not governed by a contract between the parties. It characterizes the result of a failure to make restitution under circumstances that give rise to an implied or quasi-contractual obligation to return those benefits.

The courts describe this claim in general principles. For example, courts have stated that a claim for unjust enrichment seeks to restore money where equity and good conscience require restitution; it is not premised on wrongdoing, but seeks to determine to which party, in equity, justice, and law, the money belongs; and it seeks to prevent unconscionable loss to the payor and unjust enrichment to the payee.

Because recovery based on unjust enrichment of another party relies on the court's sense of fairness or equity rather than the law, it is often referred to as the equitable doctrine of unjust enrichment.

In Maryland, the doctrine of unjust enrichment is recognized and applied by courts when one party has received a benefit unjustly at the expense of another, and there is no valid contract governing the transaction between the parties. This doctrine is rooted in the principles of equity, aiming to prevent one party from being unjustly enriched at the expense of another. Maryland courts will consider an unjust enrichment claim when a party has received a benefit that, in fairness and good conscience, they should not retain, and there is no legal contract that addresses the situation. The claim is not based on the presence of wrongdoing but on the equitable principle that it would be unjust for the recipient to retain the benefit without compensating the party who has suffered a loss. The remedy typically involves restitution, where the court orders the enriched party to return the benefit or its value to the party who has been disadvantaged. This remedy is considered equitable because it is based on the court's discretion and sense of fairness, rather than on strict legal entitlements.