Section 64 — Ignorance of law is no excuse
English translation
A person cannot excuse himself as not knowing the law in order to be relieved from criminal liability. However, if the Court is of the opinion that, according to the condition and circumstances, the doer might not have known that the law provided the act to be an offence, the Court may allow evidence to be produced before it, and if the Court believes that the doer did not know that the law so provided, the Court may inflict a punishment less than that provided by law for such offence to any extent.
This English translation is provided for reference only and has not yet been firm-verified — always rely on the Thai original.
Firm annotation
Section 64 states the maxim that ignorance of the law is no excuse, preserving the general rule that liability does not depend on the doer's knowledge of the statute. Its second limb is a narrow mitigation, not a defence: where the condition and circumstances make genuine ignorance plausible, the court may permit evidence and, if convinced, reduce the sentence below the statutory minimum to any extent. This differs sharply from Section 62, which concerns ignorance or mistake of fact, not of law; a mistaken belief about what the law provides falls under Section 64 and at most mitigates. The provision is regularly invoked, and usually rejected, by defendants unfamiliar with regulatory or specialised statutes.
Why this matters in practice
For a foreigner or first-time defendant charged under an unfamiliar Thai statute, Section 64 offers no defence, but it can open a route to a reduced sentence. The mitigation is discretionary and conditional: the defence must actively ask the court for permission to lead evidence of genuine ignorance, and simply asserting that one did not know the law will not work, especially where a conclusive legal presumption applies. Because the burden is real and the outcome uncertain, expats facing regulatory or specialised charges should get Thai legal advice early on whether a Section 64 application is realistic.
Supreme Court decisions interpreting this section
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Supreme Court Judgment No. 4366/2566 (2023)
A defendant cannot escape criminal liability by claiming not to have known that a statute applied; ignorance of the law is no excuse under Section 64.
The defendant, a Hmong hill-tribe member, argued he did not know a royal decree had brought the Building Control Act into force in his area and so lacked intent. The Court held this was an impermissible plea of ignorance of the law under Section 64 and rejected it.
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Supreme Court Judgment No. 2903/2548 (2005)
To obtain a reduced punishment for ignorance of the law under Section 64, the defendant must ask the court's permission to produce evidence; ignorance itself provides no relief.
In a methamphetamine case governed by a conclusive statutory presumption of possession for sale, the Court quoted Section 64 in full and noted that the defendant had not sought the court's permission to lead evidence of not knowing the law, so no reduction under Section 64 was available.
Curated decisions with case numbers verified against the Supreme Court database. English renderings are the firm's editorial translation for study.
Frequently asked questions
Can I avoid conviction by saying I did not know the law?
No. Section 64 states that ignorance of the law is not an excuse relieving criminal liability. At most, if the court believes you genuinely did not know, it may reduce the punishment.
How does a defendant benefit from Section 64?
The defendant must ask the court for permission to present evidence that, given the circumstances, he might not have known the act was an offence. If the court is convinced, it may impose a punishment below the statutory level to any extent.