Mrzeżyno [mʐɛˈʐɨnɔ] (German: Deep)[1] is a village with a fishing seaport in northwestern Poland, situated near the estuary of the Rega river, on the coast of the Baltic Sea in the historic region of Pomerania.

Administratively it is located in Gmina Trzebiatów, Gryfice County, West Pomeranian Voivodeship.

[2](2009) The village is situated by a special area of the conservation of nature according to the European Union's program Natura 2000.

Following Poland's fragmentation, it formed part of the Duchy of Pomerania, at various times also under Danish and Holy Roman Empire suzerainty.

Following Germany's defeat in World War II in 1945, the area became again part of Poland in accordance to the Potsdam Conference.