The Government Ministries of Thailand (Thai: กระทรวง: Krasuang) are the government agencies that compose the executive branch of the Government of Thailand. Each ministry is headed by a minister of state (Thai: รัฐมนตรีว่าการกระทรวง, RTGS: Ratthamontri Wa Kan Krasuang) and, depending on the prime minister, several deputy ministers (Thai: รัฐมนตรีช่วยว่าการกระทรวง) . The combined heads of these agencies form the Cabinet of Thailand. There are 19 ministries. The combined employees of these departments make up the civil service of Thailand.
During the Rattanakosin Period, the kingdom's administration was similar to that of the Ayutthaya Period. There were two chief ministers (Thai: อัครมหาเสนาบดี: Akkhramahasenabodi): the first running military affairs or samuhakalahom (Thai: สมุหกลาโหม), and the second Samuhanayok (Thai: สมุหนายก) for civilian affairs. The civilian ministry was divided further into four kroms (Thai: กรม), headed by a senabodi (Thai: เสนาบดี) or 'minister'. This type of administration was called the Chatusadom (Thai: จตุสดมภ์) :
Ministries
Name
Thai Name
Head
Purpose
Krom Nakhonban or Kromma Wiang
กรมนครบาล หรือ กรมเวียง
Senabodi
Cities and local administration
Kromma Wang
กรมวัง
Senabodi
Palace affairs
Kromma Khlang
กรมคลัง
Senabodi
Treasury and trade
Kromma Na
กรมนา
Senabodi
Agriculture and land
Rama V reforms
King Chulalongkorn (Rama V), who had received a European education and traveled widely, reformed the administration of the state. In 1875, he issued a royal decree to bring about this reform, dividing and creating many departments, and thereby preventing the archaic system from collapsing.
The administrative reforms of Chulalongkorn created six ministries (Thai: กระทรวง: krasuang), each headed by a minister of state or (Thai: รัฐมนตรี, RTGS: ratthamontri):
Ministries
Name
Thai Name
RTGS
Head
Purpose
Ministry of Interior
กระทรวงมหาดไทย
Krasuang Mahatthai
Minister
Local administration and the north
Ministry of War
กระทรวงยุทธนาการ
Krasuang Yuttana Thikarn
Military and the south
Ministry of Metropolitan
กระทรวงนครบาล
Krasuang Nakhonban
Bangkok and surrounding area
Ministry of the Royal Household
กระทรวงวัง
Krasuang Wang
Palace affairs
Ministry of Finance
กระทรวงการคลัง
Krasuang Kan Khlang
Finance and commerce
Ministry of Agriculture
กระทรวงเกษตราธิการ
Krasuang Kasettrathikarn
Agriculture and land
A further four were soon added:
Ministries
Name
Thai Name
Head
Purpose
Ministry of Foreign Affairs
กระทรวงการต่างประเทศ
Minister
Foreign affairs and relations
Ministry of Justice
กระทรวงยุติธรรม
Minister
Justice and the judiciary
Ministry of Transport and Communication
กระทรวงโยธาธิการ
Minister
Transport and communication (railways and telegrams)
Ministry of Education
กระทรวงธรรมการ
Minister
Education
By 1900 the entire structure was formed. The ten ministries became the center of Siamese government and rule. After the 1932 Revolution, most of the ministries were retained by the Khana Ratsadon, however from then on the ministers were chosen by the prime minister and not the king.