Unjust Enrichment and Undue Payment in Kuwaiti Law
30 July 2026

Can you recover a sum paid by mistake? The rules on unjust enrichment, undue payment, limits on recovery, and limitation periods.

The basic principle is that anyone enriched at another's expense without a legal cause must return what they gained. This fundamental rule of justice is regulated by the Kuwaiti Civil Code as an independent source of obligation.

Not compensation: an unjust-enrichment claim differs from a tort claim — it does not require proof of fault, only enrichment without a lawful cause.

1) The Concept of Unjust Enrichment

  • Principle: anyone enriched without lawful cause at another's expense must return the enrichment.
  • Independent source: a fourth source of obligation alongside contract, tort and statute.
  • Justice: prevents one person from gaining at another's expense without legal justification.
  • Subsidiary claim: the enrichment claim is inadmissible if the claimant has another remedy (contractual or tortious).
Legal basis: Articles 262 et seq. of the Kuwaiti Civil Code govern unjust enrichment and undue payment.

2) Conditions for the Claim

  1. Defendant's enrichment: they must have obtained a benefit (material or moral).
  2. Claimant's impoverishment: the claimant must have suffered a loss or been deprived of a gain.
  3. Causation: the enrichment must result from the impoverishment — i.e. at the claimant's expense.
  4. Absence of cause: there must be no legal cause justifying the enrichment (e.g. a valid contract or court order).
  5. No other remedy: the impoverished party must have no contractual or tortious claim available.
Subsidiary nature: this claim is inadmissible if the claimant can assert their right through contract or tort — it is the remedy of last resort.

3) Undue Payment

The most important practical application of unjust enrichment:

  • Definition: anyone who pays a sum not owed may recover it from the recipient.
  • Mistake in payment: whether the mistake was one of fact (believing a debt existed) or of law (not knowing the debt was extinguished).
  • Payment on another's behalf: paying someone else's debt believing it to be one's own — recovery lies against the creditor.
  • Disappearance of cause: payment made on a basis that later fails — e.g. a contract rescinded after payment.
Common example: double payment — paying an invoice twice by mistake entitles the payer to recover the excess. See compensation and civil claims.

4) Scope of Recovery

  • Rule: the enriched party must return the lesser of two values — their enrichment or the other's impoverishment.
  • Material enrichment: return of the sum or the thing in kind.
  • Moral enrichment: e.g. benefit from a service — the court assesses its value.
  • Fruits and interest: the enriched party must return fruits from the date of demand.
Not full compensation: recovery is capped at the lesser value — the impoverished party may lose part of their loss if the other's enrichment was smaller.

5) Good Faith and Bad Faith

Enriched party in good faith

  • Returns only what remains at the time of demand.
  • Not liable for what was consumed in good faith.
  • Returns fruits from the date of demand only.
  • Does not bear default interest.

Enriched party in bad faith

  • Returns everything gained or its value.
  • Liable for what was consumed or destroyed.
  • Returns fruits from the date of enrichment.
  • Bears default interest.

6) Limitation Periods

  • Short period: the claim is time-barred after three years from the day the impoverished party became aware of the right to recover.
  • Long period: in all cases, fifteen years from the date the right arose.
  • Suspension: limitation is suspended for the usual causes (minority, insanity).
  • Interruption: by judicial demand or acknowledgment.
Do not delay: the longer the wait, the harder it becomes to prove the enrichment and its value — act as soon as you discover it. See procedural defences and limitation.

7) Practical Applications

  • Building on another's land: a good-faith builder on another's land is entitled to compensation for the value of the building.
  • Tenant's improvements: a tenant who makes improvements with the owner's consent may recover their value.
  • Double payment: paying the same bill or instalment twice.
  • Services without a contract: rendering a service without a contract — e.g. rescuing another's property.
  • Contract rescission: when a contract is rescinded after partial performance, each party recovers what was delivered.
Construction: a contractor who completes extra work outside the contract and enriches the owner may claim compensation on an enrichment basis. See construction contracts.

8) Practical Guidance

For those seeking recovery

  • Document the payment or service you provided.
  • Prove there is no legal cause for the enrichment.
  • Act before the limitation period expires.
  • Consult a lawyer — the claim has precise conditions.

For those facing a claim

  • Prove a legal cause for the enrichment (contract, judgment).
  • Assert good faith if you consumed the amount.
  • Plead limitation if the demand is late.
  • Verify the claimant has no other remedy.
Paid a sum by mistake or facing an unjust-enrichment claim? Contact Attorney Meshari Obaid Al-Enezi — Yumnaak Law Firm.

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