Stelmachowo [stɛlmaˈxɔvɔ] is a village in the administrative district of Gmina Tykocin, within Białystok County, Podlaskie Voivodeship, in north-eastern Poland. It lies approximately 5 kilometres (3 mi) south of Tykocin and 29 km (18 mi) west of the regional capital Białystok.