Sir Carl August Berendsen KCMG (16 August 1890 – 12 September 1973) was a New Zealand civil servant and diplomat. After being in the Education and Labour Departments he joined the Prime Minister's Department in 1926, becoming its head in 1935. He was the creator of the Department of External Affairs, and collaborated with Michael Joseph Savage and Peter Fraser. He was Secretary for External Affairs 1928–32, Head of the Prime Minister's Department 1932–43, and Secretary of the War Cabinet 1939–43. He attended all Imperial Conferences 1926–43, and assemblies of the League of Nations and later the United Nations.