Section 421: Abuse of right, bad-faith use
Statutory text (Thai original)
การใช้สิทธิซึ่งมีแต่จะให้เกิดเสียหายแก่บุคคลอื่นนั้น ท่านว่าเป็นการอันมิชอบด้วยกฎหมาย
Verbatim from the Royal Gazette / Office of the Council of State
English translation
The exercise of a right which can only have the purpose of causing injury to another person is unlawful.
This English translation is provided for reference only and has not yet been firm-verified. Always rely on the Thai original.
Firm annotation
Section 421 is the close cousin of §5 (good faith) but in the tort chapter. It catches exercises of right where the dominant intent is to injure rather than to obtain any legitimate benefit. Classic Thai applications: a neighbour building a spite fence; a litigant filing a baseless action solely to drain the opponent; an employer terminating an employee on a technicality after the employee has reported wrongdoing. Note: §421 doesn't reach exercises of right that are merely insensitive, the plaintiff must show the dominant purpose was harm.
Why this matters in practice
Lawyers: Section 421 applies only where the right-holder has no genuine legitimate interest in the exercise and the sole purpose is to harm the other party. Courts apply this doctrine narrowly. A landowner who builds on or uses their own land in a way that incidentally harms a neighbour is not automatically liable — the plaintiff must show the action served no legitimate purpose of the right-holder. Laypersons: Even if someone technically has a legal right, using it solely to hurt you with no benefit to themselves can still be unlawful — but this is very difficult to prove.
Legislative history
Part of the original Civil and Commercial Code codification; no major subsequent amendment.
Supreme Court decisions interpreting this section
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Supreme Court Judgment No. 2573/2554 (2011)
A developer's interference with an access road that has become a statutory servitude for subdivision lot owners may constitute an abuse of rights under section 421 where the sole effect is to harm the lot owners.
A land developer had implicitly represented that a road shown in the subdivision plan would remain available. That road was encumbered as a public easement (servitude) under the applicable land-allocation regulations, and the developer was obliged to maintain it. The Court found that any interference with or denial of access to this servitude road could constitute both a violation of the servitude and, where done purely to inconvenience the lot owners, an abuse of rights under section 421.
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Supreme Court Judgment No. 8027/2546 (2003)
Section 421 does not apply where the plaintiff has not suffered special damage different from the general public; a private claimant cannot use section 421 to enforce rights against occupation of public land absent special prejudice.
The defendant occupied a strip of public land between the plaintiff's land and a public road by planting trees and building a bathroom. The plaintiff's land had not originally abutted the road, so the plaintiff had no prior access right across the public strip. The Court held this was not a case for section 421 (or section 1337): the plaintiff had not suffered special damage different from the general public, and the defendant's occupation of public land — while unlawful vis-à-vis the state — did not give the plaintiff a private cause of action for abuse of rights.
Curated decisions with case numbers verified against the Supreme Court database. English renderings are the firm's editorial translation for study.
Cited in 95 Supreme Court decisions (1949 to 2025)
Selected citing decisions
- Decision 1534/2565 (2022)
- Decision 4776/2564 (2021)
- Decision 8293/2559 (2016)
- Decision 6599/2559 (2016)
- Decision 11753-11754/2557 (2014)
- Decision 15674/2555 (2012)
- Decision 12973/2555 (2012)
- Decision 8956/2554 (2011)
This list is selected automatically, weighted towards judgments that turn on this section rather than ones that merely recite it when passing sentence. It has not yet been reviewed by the firm.
Most often cited alongside
- Section 420 32
- Section 1337 20
- Section 18 12
- Thai CPC s. 142 6
- Section 5 6
- Section 1304 4
Sections that appear in the same judgments as this one most often. The figure is the number of decisions.
Counted across the firm's corpus of 83,652 Supreme Court decisions, 1921 to 2026. The count is complete; the stated year range trims rare outliers so it describes where the citations actually sit. These figures are computed by us and are not official court statistics. How we count these, and what we measured
Related guides on ThaiLawOnline
Cite this section
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Plain citation
Civil and Commercial Code, s. 421 (Thailand) -
Academic citation
Civil and Commercial Code (Thailand), s. 421. ThaiLawOnline, https://www.thailawonline.com/thai-civil-code/section-421/ (accessed 8 August 2026). -
Thai citation
ป.พ.พ. มาตรา 421 -
Permalink
https://www.thailawonline.com/thai-civil-code/section-421/ -
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<blockquote cite="https://www.thailawonline.com/thai-civil-code/section-421/"><p>The exercise of a right which can only have the purpose of causing injury to another person is unlawful.</p><footer>Civil and Commercial Code, s. 421 (Thailand) — <a href="https://www.thailawonline.com/thai-civil-code/section-421/">ThaiLawOnline</a></footer></blockquote>
The Thai text is authoritative. The English is an unofficial translation by ThaiLawOnline, free to reuse with attribution.