William Macmahon Ball, AC (29 August 1901 – 26 December 1986) was an Australian academic and diplomat. Born in Casterton, Victoria, he was educated at Caulfield Grammar School and the University of Melbourne, where he received a Bachelor of Arts degree, Ball studied both psychology and political science as a research fellow at Melbourne and the London School of Economics respectively. He then travelled Europe as a Carnegie Travelling Fellow, and during the Munich crisis was the first foreigner allowed to visit Sachsenhausen concentration camp in several years.