The Seventh-day Adventist denomination officially entered Thailand in the year 1918 through education and medical work. The denomination founded many branches of Mission School and Mission Hospital in 1929 and expanded the work into the Northeast region of Thailand.
In the year 1935 a French missionary named A.P. Abel was able to rent one building of a palace (it was formerly the palace of M.C. Jiengkum Chumpol Na. Ayutthaya, it is located at the northeast section about 1 kilometer from Thung Sri Mueang in Ubon Ratchathani Province).
He set up an elementary school named Mission School Ubon. Originally it had 13 students and 1 teacher, but by 1938 there were 200 students, and by 1940 the school had 400 students. Sadly the school had to shut down because of World War II as Thailand was an ally of Japan and therefore all American missionaries had to go elsewhere.
After the war ended Mission School Ubon opened again in a new location. Firstly, in the year 1949, Dr. J.E. Sandess set up a clinic inside the school, which had a checkup room, a surgery room, and the most modern medical instruments that could be found at that time- before closing at a later date. Then, in 1955 the school opened again and operated until 1980.
The Ubon Mission School has now changed its name to " Ubon Adventist International Mission School" in the year 2011, functioning under the supervision of the Seventh-day Adventist Mission in Thailand, a non- profit organization. In 2013 the school earned international status from the Thai government, humbly begin with 6 students. Its curriculum is based on the American system of education, and English is the medium of instruction.