Section 21 of the Indian Contract Act, 1872: Effect of Mistake of Law
Section 21 explains what happens when parties enter into a contract under a mistake about the law. The provision draws an important distinction between a mistake concerning a law in force in India and a mistake concerning a law not in force in India.
Text and meaning of Section 21
A contract is not voidable because it was caused by a mistake as to any law in force in India; but a mistake as to a law not in force in India has the same effect as a mistake of fact.
In practical terms, a party ordinarily cannot avoid a contract merely by saying that the party misunderstood Indian law. By contrast, Section 21 treats a mistake about a law not in force in India in the same manner as a mistake of fact. Whether such a mistake actually makes an agreement void must therefore be considered with the rules governing mistake of fact, particularly Sections 20 and 22.
What does "mistake of law" mean?
A mistake of law occurs when a person is mistaken about the existence, meaning, operation or legal effect of a rule of law. Section 21 deals specifically with the contractual consequence of such a mistake. It does not say that every legal mistake is irrelevant; rather, it establishes that a contract is not voidable merely because it was caused by a mistake concerning a law in force in India.
Mistake of Indian law
If the mistake concerns a law in force in India, Section 21 expressly provides that the contract is not voidable on that ground. Thus, the mere fact that one or both parties misunderstood Indian law does not by itself give a right to rescind the contract under this section.
Mistake of foreign law
A law not in force in India is treated differently. Section 21 says that a mistake concerning such a law has the same effect as a mistake of fact. The consequences therefore depend on the applicable rules relating to factual mistake. A mutual mistake about a fact essential to the agreement may attract Section 20, while Section 22 provides that a contract is not voidable merely because one party alone was mistaken about a matter of fact.
Statutory illustration
The illustration to Section 21 concerns A and B entering into a contract under the erroneous belief that a particular debt is barred by Indian limitation law. The statutory result is that the contract is not voidable. The illustration demonstrates the rule that an erroneous understanding of Indian law does not, merely on that basis, permit avoidance of the contract.
Section 20, Section 21 and Section 22 compared
| Provision | Subject | General effect |
|---|---|---|
| Section 20 | Both parties mistaken as to an essential matter of fact | The agreement is void where the statutory requirements are satisfied. |
| Section 21 | Mistake of law | Mistake of a law in force in India does not make the contract voidable; mistake of a law not in force in India is treated like mistake of fact. |
| Section 22 | Mistake of fact by one party | The contract is not voidable merely because only one party was mistaken as to a matter of fact. |
Key points to remember
Law not in force in India: the mistake is treated as a mistake of fact.
Context matters: where foreign law is mistaken, Sections 20 and 22 may become relevant depending on whether the mistake is mutual or unilateral and whether it concerns an essential matter.
Official text of the Indian Contract Act, 1872
For the authoritative statutory text and amendments, consult the Government of India's India Code portal and the official Indian Contract Act, 1872 PDF.
Frequently asked questions
Can a contract be cancelled merely because a party misunderstood Indian law?
Section 21 says that a contract is not voidable merely because it was caused by a mistake as to a law in force in India.
Is foreign law treated as law or fact for Section 21?
For the purpose of Section 21, a mistake as to a law not in force in India has the same effect as a mistake of fact.
Does every mistake of foreign law automatically make an agreement void?
No. Because the mistake is given the same effect as a mistake of fact, the relevant requirements governing factual mistake must still be examined.
This article is a general explanation of Section 21 and is not a substitute for advice on the facts of a particular contract or dispute.