The National Agency for Administrative City Construction (Korean: 행정중심복합도시건설청; Hanja: 行政中心複合都市建設廳, NAACC) is an organization under the Ministry of Land, Infrastructure and Transport responsible for completing the Multifunctional Administrative City (MAC) in Sejong City. It was founded in 2006 and is located in Sejong City. The Agency is led by vice-ministerial-level administrator.
Unlike many other government organisations which are founded by the Government Organization Act, the Agency is founded by the special law exclusively dealt with Sejong City. Hence, the agency exclusively deals with issues related to MAC, a government complex in Sejong, and its planning and construction. However, before the Sejong City Government officially commenced its operation in 2012, it temporarily managed administrative duties of the whole Sejong.
With initial relocation of administrative agency to MAC completed, the agency is given another project of planning and constructing the regional branch of the National Assembly currently located in Seoul.
Upon MAC project's completion, it is expected that the agency will be dissolved as a division of either the Ministry of central government or Sejong city government.
Its first head, Lee Choon-hee, is currently a two-term mayor of Sejong.