Siarzewo [ɕaˈʐɛvɔ] is a village in the administrative district of Gmina Raciążek, within Aleksandrów County, Kuyavian-Pomeranian Voivodeship, in north-central Poland. It lies 3 kilometres (2 mi) east of Raciążek, 11 km (7 mi) east of Aleksandrów Kujawski, and 25 km (16 mi) south-east of Toruń.