Internal Security Operations Command (Thai: กองอำนวยการรักษาความมั่นคงภายในราชอาณาจักร; RTGS: kong amnuaikan raksa khwam mankhong phainai ratcha-anachak ) or ISOC (Thai: กอ.รมน.; RTGS: ko o ro mo no) is the internal security agency and political arm of the Royal Thai Armed Forces (RTARF). It was responsible for counterinsurgency, counterintelligence, internal security, and the suppression of leftist groups from the 1960s to the 1980s. During this period it was implicated in atrocities against activists and civilians. ISOC was implicated in a plot to assassinate Prime Minister Thaksin Shinawatra.

After Thaksin was deposed by the 2006 Thai coup d'état, the junta transformed ISOC into a government within a government, giving it wide-reaching authority over the Anti-Money Laundering Office (AMLO), the Department of Special Investigation (DSI), and the National Anti-Corruption Commission (NACC). The junta also authorized it to help provincial authorities in marketing One Tambon One Product (OTOP) products.

In June 2007, the junta approved a draft national security bill which gave ISOC sweeping powers to handle "new forms of threats" to the country. The ISOC revamp modelled it after the United States Department of Homeland Security (DHS) and gave ISOC sweeping new powers to allow the ISOC chief to implement security measures, such as searches without seeking prime ministerial approval.

ISOC's mission is to counterinsurgency, counterintelligence, counterterrorism, defend the monarchy, information and psychological warfare, internal security, promote unity, protect the public from harm, suppress threats to national security, and supporting assistance for victims of natural disasters. Nominally a civilian agency, ISOC operates under the aegis of the Office of the Prime Minister (OPM). Prime Minister General Prayut Chan-o-cha is director of ISOC. Deputy director is army chief General Narongpan Jitkaewthae.

ISOC's FY2019 budget is 10,240.1 million baht. ISOC has about 5,000-6,000 staff nationwide, excluding those working in the south, and there are 500,000-600,000 internal security volunteers, as well as tens of thousands of people in its information network.

The Communist Suppression Operations Command (CSOC) was established in 1964 with the assistance of the United States, with the aim of coordinating counterinsurgency and counterintelligence operations.

Following the 17 November 1971 coup by military dictators Thanom Kittikachorn and Praphas Charusathien, Praphas appointed himself interior minister, chief of police, and head of CSOC.

The CSOC was implicated in several atrocities in its 1970s war against leftist groups. This included the Red Drum Massacre, the mass murder of southern Thai activists by burning them alive in gasoline drums.