Hornowszczyzna [xɔrnɔfʂˈt͡ʂɨzna] is a village in the administrative district of Gmina Dziadkowice, within Siemiatycze County, Podlaskie Voivodeship, in north-eastern Poland. It lies approximately 14 kilometres (9 mi) north-east of Siemiatycze and 68 km (42 mi) south of the regional capital Białystok.