The Council for National Security (Thai: คณะมนตรีความมั่นคงแห่งชาติ; rtgs: Khana Montri Khwam Man Khong Haeng Chat) or CNS (Thai: คมช.), formerly known as the Council for Democratic Reform (Thai: คณะปฏิรูปการปกครองในระบอบประชาธิปไตยอันมีพระมหากษัตริย์ทรงเป็นประมุข; rtgs: Khana Patirup Kan Pok Khrong Nai Rabop Prachathipatai An Mi Phra Maha Kasat Song Pen Pramuk) or CDR (Thai: คปค.), was the military junta that governed Thailand after staging a coup d'état against Prime Minister Thaksin Shinawatra.
The council was led by Army Commander General Sonthi Boonyaratglin who acted as the prime minister and the cabinet, until General Surayud Chulanont was appointed as a new prime minister. Under the CNS-drafted interim constitution, the Council continued to maintain considerable power, particularly over the drafting of a permanent constitution.
The council came to an end by operation of section 298, paragraph 2, of the Constitution of the Kingdom of Thailand, Buddhist Era 2550 (2007), which prescribes: "The National Security Council...shall vacate office en masse at the time when the Council of Ministers carrying out the administration of state affairs on the date of promulgation of this Constitution vacate office."