Sukhothai was the first Thai kingdom. It was founded in 1238 by two Thai governors, Khun Bang Klang Thao (Si Inthrathit) and Khun Pha Muang who rebelled against the Khmers; and gave independence to the region. Sukhothai period was the most flourishing period of Thailand. It gained independence in 1238 and quickly expanded its boundary of influence. Sukhothai period was considered to be a golden age of Thai culture. During that time in the history, everybody could say that "There are fish in the water and rice in the fields". The boundary of Sukhothai stretched from Lampang in the north to Vientiane, in present day Laos and the south to the Malay Peninsula.

During this time Thai had strong friendship with neighboring countries. It absorbed elements of various civilizations which they came into contact. Thai maintained and advanced their culture with China. The potters entered Thai artistry and extensive trade was established with Cambodia and India.

After the death of Khun Pha Muang in 1279, Ramkhamhaeng King, the third son of Si Inthrahit, ascended to the throne. Under the Ramkhamhaeng King, Sukhothai had strong friendship with neighboring China. Ramkhamhaeng King organized a writing system which became the basis for writing and eventually developed to be the modern Thai alphabet.