A quasi-contract (or implied-in-law contract or constructive contract) is a
fictional Fiction is any creative workA creative work is a manifestation of creative effort including fine artwork (sculpture Sculpture is the branch of the visual arts that operates in three dimensions. It is one of the plastic arts. Durable sculp ...
contract A contract is a legally binding agreement that defines and governs the rights and duties between or among its parties Image:'Hip, Hip, Hurrah! Artist Festival at Skagen', by Peder Severin Krøyer (1888) Demisted with DXO PhotoLab Clearview; ...

recognised by a court. The notion of a quasi-contract can be traced to
Roman law Roman law is the law, legal system of ancient Rome, including the legal developments spanning over a thousand years of jurisprudence, from the Twelve Tables (c. 449 BC), to the ''Corpus Juris Civilis'' (AD 529) ordered by Eastern Roman emperor J ...
and is still a concept used in some modern legal systems.


common law In law, common law (also known as judicial precedent or judge-made law, or case law) is the body of law created by judges and similar quasi-judicial tribunals by virtue of being stated in written opinions. ''Black's Law Dictionary'' is the most-us ...
jurisdictions, the law of quasi-contract can be traced to the medieval
form of action The forms of action were the different procedures by which a legal claim A cause of action, in law Law is a system A system is a group of Interaction, interacting or interrelated elements that act according to a set of rules to form a uni ...
known as ''indebitatus assumpsit''. In essence, the plaintiff would recover a money sum from the defendant ''as if'' the defendant had promised to pay it: that is, ''as if'' there were a contract subsisting between the parties. The defendant's promise—their agreement to be bound by the "contract"—was implied by law. The law of quasi-contract was generally used to enforce restitutionary obligations. The form of action known as ''indebitatus assumpsit'' came to include various sub-forms known as the common money counts. The most important of these for the later development of the law of quasi-contract included: (i) actions for money had and received to the plaintiff's use; (ii) actions for money paid to the defendant's use; (iii) ''
quantum meruit ''Quantum meruit'' is a Latin phrase meaning "what one has earned". In the context of contract law, it means something along the lines of "reasonable value of services". In the United States, the elements of ''quantum meruit'' are determined by s ...
''; and (iv) ''quantum valebat''. Quasi-contractual actions were generally (but not exclusively) used to remedy what would now be called
unjust enrichment In laws of equity, unjust enrichment occurs when one person is enriched at the expense of another in circumstances that the law sees as unjust. Where an individual is unjustly enriched, the law imposes an obligation upon the recipient to make res ...
. In most common law jurisdictions the law of quasi-contract has been superseded by the law of unjust enrichment.See generally, Mitchell et al, '' Goff & Jones Law of Unjust Enrichment'' (8th ed, 2011); Carter et al, ''Mason & Carter's Restitution Law in Australia'' (2nd ed, 2008); Graham Virgo, ''The Principles of the Law of Restitution'' (3rd ed, 2015)

Quasi-contract and contract

A quasi-contract was distinct from a contract implied in fact. * ''Contract implied in fact.'' A person's assent to be bound by an agreement can be expressed or implied. In the latter case, assuming the requisite formalities for a valid contract are met, there is a perfectly normal contract. The only distinction between a contract arising by express agreement between two people and a contract implied-in-fact is that the latter was recognised by a court drawing inferences from facts proved at trial. When the plaintiff sued on either sort of contract, she was suing in the law of contract in respect of a consensually assumed obligation and her remedy for the defendant's breach was damages. * ''Quasi-contract''. In contrast, quasi-contract refers to situations in which a defendant is bound ''as if'' there were a contract. When the plaintiff sued on such a 'contract' by bringing an action of ''indebitatus assumpsit'', she was not enforcing some consensually assumed obligation, but rather an obligation imposed by law.

See also

The law of contract
The law of contract
** Implied-in-fact contract **
Promissory estoppel A promise is a commitment by someone to do or not do something. As a noun A noun (from Latin ''nōmen'', literally ''name'') is a word that functions as the name of a specific object or set of objects, such as living creatures, places, actions, ...
The Law of Restitution
The Law of Restitution
Unjust enrichment In laws of equity, unjust enrichment occurs when one person is enriched at the expense of another in circumstances that the law sees as unjust. Where an individual is unjustly enriched, the law imposes an obligation upon the recipient to make res ...
** Officious intermeddler *
Negotiorum gestio''Negotiorum gestio'' (, Latin for "management of business") is a form of spontaneous voluntary agency (law), agency in which an intervenor or intermeddler, the ''gestor'', acts on behalf and for the benefit of a principal (commercial law), principal ...




* ''The Law of Quasi-Contract'' by S. J. Stoljar; Sydney : Law Book Co. of Australasia, 1964 {{DEFAULTSORT:Quasi-Contract Contract law Law of obligations Legal fictions