Mahmoud Hessaby (Persian: سید محمود حسابی‎ alternative spellings: Mahmood Hesabi) (February 23, 1903, Tehran – September 3, 1992, Geneva) was an Iranian scientist, researcher and professor of University of Tehran. During the congress on "60 years of physics in Iran" the services rendered by him were deeply appreciated and he was called "the father of modern physics in Iran".