Section 86 — Supporter or accessory to an offence
English translation
Whoever, by any means whatever, aids or facilitates another person's commission of an offence, before or at the time of the commission, even though the offender is not aware of that aid or facilitation, is a supporter in the commission of the offence and shall be liable to two thirds of the punishment prescribed for the offence supported.
This English translation is provided for reference only and has not yet been firm-verified — always rely on the Thai original.
Firm annotation
Section 86, in Book 1 within the Title on Principals and Supporters, defines accessory liability. Its elements are: conduct that aids or facilitates another's offence, by any means, occurring before or at the time of the commission, and directed at an offence that is in fact committed by the principal. A distinctive feature is that the principal need not be aware of the help, so one-sided assistance still counts. The supporter is liable to two thirds of the penalty for the offence supported, the same fraction as an ordinary attempt but plainly less than a co-principal's full penalty under section 83. The line from section 83 is participation versus mere assistance; the line from section 84 is helping an offence versus causing it. Note that special statutes can override the two-thirds rule: in some narcotics offences a supporter is made liable to the same penalty as a principal.
Why this matters in practice
For an accessory, the practical stakes are whether the role was mere assistance, capped at two thirds under section 86, or full participation as a co-principal under section 83 at the whole penalty, so characterising the conduct is central. Watch for the special-law trap: in certain narcotics prosecutions a governing statute makes the supporter liable to the same punishment as the principal, stripping away the two-thirds discount, so the default under the Penal Code should not be assumed. Because the principal's awareness is irrelevant, providing tools, information or access can attract liability even without any agreement with the offender.
Supreme Court decisions interpreting this section
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Supreme Court Judgment No. 4040/2567 (2024)
A person who aids the commission of an offence is a supporter under section 86 and is convicted and punished on that basis.
The Supreme Court reversed an acquittal and found the defendant guilty of supporting participation in a transnational organised crime, under the special statute read with section 86, sentencing the defendant as a supporter before reducing the term for a useful investigation statement.
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Supreme Court Judgment No. 7422/2568 (2025)
Under a special narcotics statute a supporter may be made liable to the same punishment as the principal, overriding the two-thirds reduction that section 86 otherwise provides.
In a narcotics prosecution charged under the special measures act together with section 86, the decision records that the defendant was liable to the same penalty as a principal, illustrating how a special statute can displace the ordinary two-thirds cap for supporters.
Curated decisions with case numbers verified against the Supreme Court database. English renderings are the firm's editorial translation for study.
Frequently asked questions
What penalty does a supporter face in Thailand?
Under section 86 a supporter is liable to two thirds of the punishment prescribed for the offence supported, which is less than a co-principal's full penalty under section 83.
Can you be a supporter if the main offender did not know you helped?
Yes. Section 86 expressly covers aid or facilitation even where the offender is not aware of it, so one-sided help before or during the offence can still make you a supporter.