Mandiga is a town in Western Australia, in the Shire of Mount Marshall. It is located between the towns of Koorda and Mukinbudin in the Wheatbelt region. Originating as a railway siding on the Wyalkatchem to Mount Marshall railway line, which was opened in 1917, a town had been considered in the area in 1916 when the railway was planned. The town was gazetted in 1919, but little development took place in the town.