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.

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.

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.

Its first head, Lee Choon-hee, is currently a two-term mayor of Sejong.