Rayong Province (Thai: ระยอง; Chong: ราย็อง) is a province (changwat) of Thailand. Neighboring provinces are (from west clockwise) Chonburi, and Chanthaburi. To the south is the Gulf of Thailand.
King Taksin (of Thailand) came to Rayong after the fall of Ayutthaya. During a short stay in Rayong he built a navy, and then went on to Chantaburi to assemble forces to fight back against the Burmese. There is a shrine in Rayong where local people pay respects to Taksin.
Although the north is hilly, the province consists mostly of low coastal plains. Several islands in the Gulf of Thailand belong to the province, including the popular tourist destinations, Ko Samet, Ko Mun, and Ko Khod.