Thailand · Citizenship
Thai Citizenship for Foreign Residents
Thailand's Nationality Act sets a short list of naturalization criteria, but approval rests with the Minister of Interior and requires Royal Assent. There is no citizenship-by-investment program, and naturalized citizens who keep using another nationality risk revocation.
- Startup route
- SMART Visa (SMART S)
- Minimum capital
- THB 600,000 personal deposit held for 3 months
- Permanent residence
- 3+ years of non-immigrant extensions; annual quota
- Citizenship
- 5 consecutive years' domicile; Thai required
Naturalization under the Nationality Act, B.E. 2508 (1965)
Section 10 of the Nationality Act allows a foreigner to apply after reaching legal age under Thai law and the law of their own country, showing good behavior and a well-founded occupation, and having a domicile in Thailand for at least five consecutive years up to the filing date. Applicants must also have knowledge of Thai as set by ministerial regulation. Section 11 waives the domicile and language conditions for people who have rendered distinguished service to Thailand, for spouses and children of naturalized citizens, for former Thai nationals and for husbands of Thai citizens. Approval is at the Minister's discretion and is then submitted for Royal Assent, after which the applicant takes an oath of allegiance.
- Domicile
- 5 consecutive years before filing
- Language
- Knowledge of Thai, as set by ministerial regulation
- Decision
- Minister's discretion, then Royal Assent
- Oath
- Oath of allegiance after Royal Assent
- Dual citizenship
- Using a former nationality can lead to revocation
- Government fee
- Varies; confirm with the Ministry of Interior
Requirements
- Be of legal age under Thai law and the law of your current nationality.
- Show good behavior and a well-founded occupation.
- Have a domicile in Thailand for at least five consecutive years before applying.
- Have the knowledge of Thai required by ministerial regulation.
How to apply
- Prepare evidence of domicile, occupation, income and tax payments.
- File the application in the form set by ministerial regulation.
- Await the Minister's decision and Royal Assent.
- Take the oath of allegiance; naturalization takes effect on publication in the Government Gazette.
Dual nationality under Thai law
The Nationality Act contains no express duty to renounce a previous nationality on naturalization, but it lets the Minister revoke Thai nationality acquired by naturalization if there is evidence the person still uses the former nationality, keeps the nationality of a country at war with Thailand, lives abroad without a Thai domicile for more than five years, or acts against national security or public order. Thai nationals who naturalize elsewhere lose Thai nationality under Section 22. Founders should treat Thai citizenship as a decision that may affect an existing passport.
Questions and answers
Does Thailand require permanent residence before naturalization?
Section 10 of the Nationality Act speaks of a domicile in Thailand for at least five consecutive years rather than naming a particular visa. The Act leaves detailed procedure to ministerial regulation, so applicants should confirm with the Ministry of Interior how domicile is evidenced in their case.
Can a naturalized Thai citizen keep another passport?
The Act does not expressly require renunciation, but naturalized citizens can lose Thai nationality if there is evidence they still use their former nationality, or if they retain the nationality of a country at war with Thailand. Thai nationals who acquire another citizenship by naturalization lose Thai nationality.
Is there a Thai citizenship-by-investment program?
No. Investment can support a long-term visa, such as the LTR wealthy global citizen category, or a residence permit under the investment category, but citizenship still requires naturalization under the Nationality Act, including five years' domicile, a stable occupation and knowledge of Thai.
Official sources
- Nationality Act, B.E. 2508 (1965), unofficial translation (Office of the Council of State)report.dopa.go.th
- Thai Nationality Renunciation and Reapplication (Royal Thai Embassy, Brussels)brussels.thaiembassy.org
- LTR Visa Thailand (Long-Term Resident Program, BOI)ltr.boi.go.th
Reviewed October 2026. Immigration rules change often. Confirm the current requirements with the official authority or a licensed adviser before applying.
Your path in Thailand.
Startup visa
SMART S for certified startup founders; BOI endorsement, up to 2 years
02Temporary residence
Renew SMART S, or move to a 10-year LTR visa or Thailand Privilege
03Permanent residence
Residence permit after 3 years of extensions, within an annual quota
04Citizenship
Naturalization after 5 years' domicile, Thai language and Royal Assent