Marynowo [marɨˈnɔvɔ] is a village in the administrative district of Gmina Sejny, within Sejny County, Podlaskie Voivodeship.

It is situated in north-eastern Poland, close to the border with Lithuania.

It lies approximately 5 kilometres (3 mi) south-west of Sejny and 110 km (68 mi) north of the regional capital Białystok.