Legal Dictionary


Legal Definition of quasi-contract


Related terms

Definition of quasi-contract


quasi-contract (plural quasi-contracts)

  1. (law) An obligation created by the law in the absence of an agreement or contract; not based upon the intentions or expressions of the parties.

Further reading

A quasi-contract, also called an implied-in-law contract,[1] is a legal substitute for a contract. A quasi-contract is a contract that should have been formed, even though in actuality it was not. It is used when a court wishes to create an obligation upon a non-contracting party to avoid injustice and to ensure fairness.[2] [1] [3] It is invoked in circumstances of unjust enrichment.[3]

Generally an actual or implied-in-fact contract is required for the defendant to be liable for services rendered, and a person who provides a service uninvited is an officious intermeddler who is not entitled to compensation. "Would-be plaintiffs cannot deliver unordered goods or services and demand payment for the benefit...A corollary is that one who does have an enforceable contract is bound by the contract's terms: subject to a few controversial exceptions, she cannot sue for restitution of the value of benefits conferred..." [4] However, in many jurisdictions under certain circumstances plaintiffs may be entitled to restitution under quasi-contract (as with the example of Oklahoma below).

Quasi-contracts are defined to be "the lawful and purely voluntary acts of a man, from which there results any obligation whatever to a third person, and sometime a reciprocal obligation between the parties."[5] It "is not legitimately done, but the terms are accepted and followed as if there is a legitimate contract."[6]


According to the Oklahoma pattern jury instructions, the elements of quasi-contract are:

    # Plaintiff furnished / rendered valuable goods / services to Defendant with a reasonable expectation of being compensated;
    1. Defendant knowingly accepted the benefits of the goods / services; and
    2. Defendant would be unfairly benefited by the services / receiving the goods if no compensation were paid to the Plaintiff.�[7]

Knowledge, the second element, is required, and if the defendant had no knowledge of the benefits, there would be no contract of any kind, even a quasi-contract.[1]


An example of a quasi-contract is the case of a plumber who accidentally installs a sprinkler system in the lawn of the wrong house. The owner of the house had learned the previous day that his neighbor was getting new sprinklers. That morning, he sees the plumber installing them in his own lawn. Pleased at the mistake, he says nothing, and then refuses to pay when the plumber hands him the bill. Will the man be held liable for payment? Yes, if it could be proven that the man knew that the sprinklers were being installed mistakenly, the court would make him pay because of a quasi-contract. If that knowledge could not be proven, he would not be liable.

Examples of quasi-contracts vary by jurisdiction. A painter, who mistakenly paints a house with the owner's knowledge, can sue in court to get paid.[1] A mechanic who fixes the brakes to a car as requested, but who also makes repairs to the axle (without which the brakes would not function properly), has an implied quasi-contract.[2] For a casual job, there is almost never a written contract, but often a quasi-contract.[6] A homebuilder who signs a contract with a purported agent, who actually has no authority, can recover the cost of the services and materials from the homeowner.[3]


  1. Marshall Wick, Notes for BUS 447, Gallaudet University, found at Gallaudet University Website. Accessed June 30, 2008.
  2. Website. Accessed June 30, 2008.
  3. American Law Encyclopedia Website. Accessed June 30, 2008.
  4. Douglas Laycock, Modern American Remedies, 3rd edition (2002) pg. 566
  5. The Lectric Law Library's Lexicon.
  6. Legal Explanations Website. Accessed June 30, 2008.
  7. Oklahoma Uniform Jury Instructions, Civil, Chapter 23, Article PART ONE, Section Instruction 23.10 - QUASI-CONTRACT (QUANTUM MERUIT OR QUANTUM VALEBANT), found at Oklahoma Uniform Jury Instructions Website. Accessed June 30, 2008.


  1. Wiktionary. Published under the Creative Commons Attribution/Share-Alike License.


1.     lex fori
2.     landed property
3.     lex situs
4.     respondent
5.     default judgment
6.     tort law
7.     living will
8.     lex causae
9.     law
10.     salacious