The Public Debt Management Office (PDMO) was established by the Cabinet resolution on October 1, 1999, initially as an agency under the Office of the Permanent Secretary of the Ministry of Finance. It was later elevated to department level under the Ministry of Finance according to the Reorganization of Ministries, Departments and Sub-departments Act B.E. 2545 on October 9, 2002, by merging the operations of two agencies: the Fiscal Policy Office (in the areas of Borrowing Policy Division, Capital Market Borrowing Policy Division, Social Investment Project Division, and Advisory Data Center) and the Comptroller General's Department (in the areas of public debt and treasury operations and the Public Debt and Treasury Analysis Group).

The merger of these two agencies was aimed at creating unity in Thailand's public debt management by giving PDMO comprehensive responsibility for the country's debt management as a single agency. PDMO is responsible for formulating overall national debt management policy, overseeing and managing public debt risks including government guarantees and obligations, implementing debt issuance, debt management, and government debt service management, as well as developing public debt information database systems for the country.