Gdynia [ˈɡdɨɲa] (Kashubian:Gdiniô) is a city in the Pomeranian Voivodeship of Poland and an important seaport of Gdańsk Bay on the south coast of the Baltic Sea.

Located in Kashubia in Eastern Pomerania, Gdynia is part of a conurbation with the spa town of Sopot, the city of Gdańsk and suburban communities, which together form a metropolitan area called the Tricity (Trójmiasto), with a population of over a million people.