Brzostowo [bʐɔsˈtɔvɔ] is a village in the administrative district of Gmina Jedwabne, within Łomża County, Podlaskie Voivodeship, in north-eastern Poland. It lies approximately 11 kilometres (7 mi) east of Jedwabne, 30 km (19 mi) north-east of Łomża, and 53 km (33 mi) north-west of the regional capital Białystok.