How to Get Thai Citizenship

Reviewed by ThaiLawOnline, a licensed Thai law firm practising in Thailand since 2006. Thai lawyer of record: Wichuda Atthamethakon, LL.M., Thai Bar Licence 3149/2556.

Last updated on 22 September 2026

Last reviewed: 22 September 2026. Every statutory statement on this page was read in Thai against the consolidated text of the Nationality Act B.E. 2508 as amended to the Nationality Act (No. 5) B.E. 2555, from the central legal register (law.go.th): sections 5, 7, 9, 10, 11, 12, 13, 14, 19, 22, 23 and 24, and the fee schedule annexed to the Act. Section 11(4), the exemption for the husband of a Thai national, was also read in the amending Act that added it, the Nationality Act (No. 4) B.E. 2551. The income figure, the interview, the anthems and the processing time are administrative practice, not provisions of the Act, and are marked as such below.

Most foreigners who end up applying for Thai citizenship did not plan to. They came for a job, a marriage or a few years, and a decade later Thailand is home while the law still treats them as visitors. That means an extension every year, TM30 and 90-day reports, a work permit tied to one employer, a re-entry permit for every trip, no land in your own name and, in the sectors the Foreign Business Act restricts, no majority stake in your own company.

A Thai national carries none of that. A naturalised Thai is Thai for every purpose, including the Land Code and the Foreign Business Act. This guide explains who can become Thai, what the Nationality Act actually requires, where the authorities add requirements of their own, and how an application moves from filing to the Royal Gazette.

The four ways to become Thai

1. By birth (section 7). A person born of a Thai father or a Thai mother is Thai from birth, whether born in Thailand or abroad. The child of a Thai parent needs no application for nationality.
2. A foreign wife of a Thai national (section 9). An alien woman married to a Thai may apply for Thai nationality directly. This is not naturalisation, and the section 10 conditions do not apply to it. The grant is in the discretion of the Minister.
3. Naturalisation (sections 10 to 12). The route for everyone else, including the foreign husband of a Thai national.
4. Recovery (sections 23 and 24). For a person who was Thai and lost that nationality, for example a Thai who renounced it on marrying a foreigner and whose marriage has since ended.

What naturalisation requires under section 10

Section 10 sets five conditions. The applicant must:

1. be of full age under Thai law and under the law of their own nationality;
2. be of good behaviour;
3. have an established occupation;
4. have had a domicile in Thailand continuously for at least five years up to the date of the application; and
5. have knowledge of the Thai language as prescribed by ministerial regulation.

The Act sets no income figure and does not mention permanent residence. In practice the five years of domicile are counted from a grant of permanent residence, so an applicant who is not exempt usually spends three years on extensions of stay, obtains a residence permit, lives in Thailand as a resident for five years and only then files for citizenship.

Who is excused the five years and the language requirement

Section 11 disapplies conditions (4), the five years of domicile, and (5), the Thai language, for four groups of applicants:

• a person who has done something of special merit for Thailand or rendered a service to the government that the Minister considers appropriate;
• the child, wife or husband of a person who has been naturalised Thai or has recovered Thai nationality;
• a person who formerly held Thai nationality; and
• the husband of a Thai national, a limb added by section 9 of the Nationality Act (No. 4) B.E. 2551.

The exemption covers only those two conditions. A husband of a Thai must still be of age, of good behaviour and in an established occupation, and the authorities still assess him on the criteria described below.

Married to a Thai: husbands and wives take different routes

The Act treats the two spouses differently, and the difference decides which application you file.

• A foreign husband naturalises under section 10. Section 11(4) removes the five years of domicile and the Thai language requirement, so he does not need permanent residence first.
• A foreign wife does not naturalise at all. She applies under section 9, in the form and by the procedure set by ministerial regulation, and the Minister decides in his discretion. Section 11(4) does not mention her, and no other limb of section 11 covers the wife of a Thai by birth.

Same-sex couples should read the drafting with care. Sections 9 and 11(4) are written for a wife and a husband respectively, and the Marriage Equality Act did not rewrite them. See our guide to same-sex marriage in Thailand on which provisions carried across and which did not.

What the authorities look for beyond the Act

The Act gives the Minister discretion, and the Ministry of Interior and Special Branch apply their own criteria when they exercise it. These are administrative practice, not law, and they change more often than the Act does, so confirm the current figures before you file:

• Income. An applicant married to a Thai national and working in Thailand is expected to earn at least 40,000 baht a month, with tax returns to prove it. A higher figure applies to applicants who are not married to a Thai.
• Interview. The interview is conducted in Thai, and applicants are commonly asked to sing the National Anthem and the Royal Anthem.
• Documents. Expect to provide your passport and residence documents, work permit and tax records, marriage and birth certificates where relevant, a police clearance and photographs. Foreign documents usually need translation and legalisation.

How an application moves, and what it costs

In Bangkok, naturalisation applications are lodged with the Special Branch Bureau of the Royal Thai Police, at the National Police headquarters on Rama 1 Road. Section 12 then sets the sequence:

1. the application is filed in the form and by the procedure set by ministerial regulation;
2. the Minister decides whether to allow it, in his discretion;
3. if he allows it, royal permission is sought;
4. once royal permission is granted, the applicant takes an oath of loyalty to Thailand; and
5. the naturalisation takes effect only when it is published in the Royal Gazette (section 5), after which the naturalisation certificate is issued.

An applicant with minor children domiciled in Thailand may apply for them at the same time. Section 12 excuses those children the conditions of age, occupation, domicile and language.

Fees. The schedule annexed to the Act sets ceilings, and section 6 lets the Minister charge any amount up to them: 10,000 baht for a naturalisation application, 5,000 baht for each minor child applying with a parent, 1,000 baht for the naturalisation certificate and 2,000 baht for an application to recover Thai nationality. The fee actually charged is set by ministerial regulation within those ceilings, so confirm it when you file.

Time. Nothing in the Act fixes a timetable. In practice the file takes several years from filing to the Gazette notice, and for an applicant who needs permanent residence first the whole path runs to a decade or more.

Keeping your current passport

The Nationality Act contains no general rule that a foreigner who naturalises as Thai must give up the nationality they already hold. Whether your other country allows you to keep its nationality is a question for the law of that country, and you should check it before you apply.

For people who are Thai already, section 22 lists the ways Thai nationality is lost: naturalising as an alien, renouncing it, or having it revoked. Acquiring another nationality by descent, marriage or registration is none of those. Section 14 is narrower than it is often described: it applies to a Thai born while a parent was an alien who also holds the nationality of that parent, and requires anyone in that position who wishes to keep the other nationality to renounce Thai nationality within one year of turning twenty. Section 13 lets a Thai married to a foreigner, who may take the nationality of the spouse under the law of the spouse, renounce Thai nationality if they wish to, and section 23 lets them recover it once the marriage has ended.

Can naturalisation be taken away?

Yes, but only on the grounds in section 19, which applies only to people who became Thai by naturalisation: concealing a fact or making a false statement on a material point in the application; evidence that the person still uses their former nationality; acts affecting national security, contrary to the interests of the State or insulting to the nation; acts contrary to public order or good morals; living abroad without a domicile in Thailand for more than five years; and still holding the nationality of a country at war with Thailand.

Where to start

The first question is eligibility: which route your marriage, residence and income actually support, and whether any exemption in section 11 applies to you. If you need permanent residence first, our permanent residency guide sets out the annual quota and our fixed fee for the application. For a review of your own position, book an immigration consultation.

Frequently asked questions