Arunachalam Mahadeva, KCMG (Tamil: அருணாசலம் மகாதேவா, romanized: Aruṇācalam Makātēvā; 5 October 1885 – 15 April 1966) was a Ceylon Tamil lawyer, politician and diplomat. He served as Minister of Home Affairs (1942-1946) and High Commissioner to India (1948-1949).