For a visit of up to 30 days:
(in process of being extended to 45 days by the government of Thailand)
Passport holders from the following countries/territory are not required to obtain a visa when entering Thailand for tourism purposes and will be permitted to stay in the Kingdom for a period of not exceeding 30 (45) days on each visit:

Tourist Visa Exemption Scheme: Andora, Australia, Austria, Bahrain, Belgium, Brazil, Brunei Darussalam, Canada, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hong Kong, Hungary, Iceland, Indonesia, Ireland, Israel, Italy, Japan, Korea, Kuwait, Latvia, Liechtenstein. Lithuania, Luxembourg, Malaysia, Maldives, Mauritius, Monaco, Netherlands, New Zealand, Norway, Oman, Peru, Philippines, Poland, Portugal, Qatar, San Marino, Singapore, Slovakia, Slovenia, Spain, South Africa, Sweden, Switzerland, Ukraine, Sweden, UAE, UK, USA, Vietnam

Bilateral Agreement arrangement: Lao, Macau, Mongolia, Russia

For a visit of up to 90 days:
Passport holders from the following countries/territory are not required to obtain a visa when entering Thailand for tourism purposes and will be permitted to stay in the Kingdom for a period of not exceeding 90 days on each visit:

Bilateral Agreement arrangement: Argentina, Brazil, Chile, Korea, Peru