The Council for National Security (Thai: คณะมนตรีความมั่นคงแห่งชาติ; RTGS: Khana Montri Khwam Mankhong Haeng Chat) or, in brief, CNS (Thai: คมช.), formerly known as the Council for Democratic Reform (Thai: คณะปฏิรูปการปกครองในระบอบประชาธิปไตย อันมีพระมหากษัตริย์ทรงเป็นประมุข; RTGS: Khana Patirup Kan Pokkhrong Nai Rabop Prachathipatai An Mi Phra Maha Kasat Song Pen Pramuk) or, in brief, CDR (Thai: คปค.), also translated as the Council for Democratic Reform under the Constitutional Monarchy, was the name of the military regime that governed Thailand following the 2006 pronunciamiento ousting Prime Minister Thaksin Shinawatra.

It was led by Army Commander General Sonthi Boonyaratglin, who claimed powers equivalent to Prime Minister, before appointing Surayud Chulanont as Prime Minister of Thailand. Under the CNS-drafted interim constitution, the Council continues to maintain considerable power, particularly over the drafting of a permanent constitution.

The Council has come to an end by virtue 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."