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 Wisconsin, 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 them. This doctrine is rooted in the principles of equity, aiming to prevent one party from being unjustly enriched at the expense of another. Wisconsin courts will consider an unjust enrichment claim by examining whether the enrichment of one party is unjust and whether restitution is appropriate under the circumstances. The claim is not based on the presence of wrongful conduct but rather on the notion that it would be inequitable for the party to retain the benefit without compensating the other party. The remedy typically involves the return of the benefit or its value to the party who has been disadvantaged. This equitable relief is discretionary and is intended to correct situations where the retention of the benefit would be contrary to justice and good conscience.