Section 30 — Injured person joining the prosecutor
Statutory text (Thai original)
คดีอาญาใดซึ่งพนักงานอัยการยื่นฟ้องต่อศาลแล้ว ผู้เสียหายจะยื่นคำร้องขอเข้าร่วมเป็นโจทก์ในระยะใดระหว่างพิจารณาก่อนศาลชั้นต้นพิพากษาคดีนั้นก็ได้
English translation
In any criminal case which the public prosecutor has filed with the court, the injured person may submit a motion to join as a co-plaintiff at any stage during the trial before the court of first instance renders judgment in that case.
This English translation is provided for reference only and has not yet been firm-verified — always rely on the Thai original.
Firm annotation
Section 30 lets the injured person add their voice to a prosecution the public prosecutor is already running, becoming a joint plaintiff. The right is time bound: the motion must be filed during the trial and before the court of first instance renders judgment. To join, the applicant must be a lawful injured person, which is assessed under Section 2(4); a person who was contributorily at fault, or whose representative lacks authority under Section 5, cannot join. This section pairs with Section 31, where the roles are reversed and the prosecutor joins a case the injured person filed.
Why this matters in practice
Joining as co-plaintiff lets you present evidence, examine witnesses, and appeal, instead of relying entirely on the prosecutor, but you must move before the first-instance judgment or lose the chance. Be ready to prove you are a lawful injured person, because a court can and will refuse or later strike out an applicant who was partly at fault. If a prosecutor is running a case that harmed you, ask a lawyer whether to join as a co-plaintiff.
Supreme Court decisions interpreting this section
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Supreme Court Judgment No. 324/2568 (2025)
Where the deceased was contributorily negligent and is therefore not a lawful injured person under Section 2(4), the surviving spouse cannot act for the deceased and cannot join the prosecutor as co-plaintiff under Section 30.
Because the deceased shared in the negligence, he was not an injured person by law for the offence of causing death by negligence. His wife accordingly had no power under Section 5(2) to act for him and no power to join as co-plaintiff under Section 30. The lower courts were wrong to allow her to join, a public-order point the Supreme Court raised on its own.
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Supreme Court Judgment No. 1196/2564 (2021)
A shooting victim who did not participate in the offence is a lawful injured person and has the power to join the prosecutor as co-plaintiff under Section 30.
The defendant shot the first co-plaintiff, who survived, making the act attempted murder. Because the co-plaintiff had no part in the offence, he was a lawful injured person with power to join the prosecution as co-plaintiff under Section 30.
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Supreme Court Judgment No. 618/2568 (2025)
Only a person who is the injured party in the offence the public prosecutor charged may join as co-plaintiff; one who is not the injured person has no right to join under Section 30.
In an Intellectual Property and International Trade Court case, applying Section 30 through the special court statute, the first applicant was not the injured person in the charged offence and therefore had no right to join as co-plaintiff, and consequently no right to seek compensation.
Curated decisions with case numbers verified against the Supreme Court database. English renderings are the firm's editorial translation for study.
Frequently asked questions
How does a victim join the prosecutor's criminal case?
Under Section 30 the injured person files a motion to join as co-plaintiff. It must be filed during the trial and before the court of first instance gives judgment.
What is the deadline to join as co-plaintiff?
The motion must be made before the court of first instance renders judgment. After that judgment, joining under Section 30 is no longer possible.
Can a partly at-fault victim still join as co-plaintiff?
Not necessarily. Only a lawful injured person may join. If the victim was contributorily at fault, a court may hold they are not an injured person by law and refuse the request.