Sar Tang-e Mahmud (Persian: سرتنگ محمود, also Romanized as Sar Tang-e Maḩmūd; also known as Sar Tang-e Maḩmūdī) is a village in Mashayekh Rural District, Naghan District, Kiar County, Chaharmahal and Bakhtiari Province, Iran. At the 2006 census, its population was 475, in 108 families.