Trzeciny [tʂɛˈt͡ɕinɨ] is a village in the administrative district of Gmina Wysokie Mazowieckie, within Wysokie Mazowieckie County, Podlaskie Voivodeship, in north-eastern Poland. It lies approximately 6 kilometres (4 mi) west of Wysokie Mazowieckie and 55 km (34 mi) south-west of the regional capital Białystok.