The Ukrainian (Greek) Catholic Eparchy of Olsztyn–Gdańsk (Olsztyn–Gdańsk of the Ukrainians) is a suffragan eparchy (Eastern Catholic diocese) in the ecclesiastical province of the metropolis of Przemyśl-Warsaw [pl], which covers some part of Poland for the Ukrainian Greek Catholic Church (Byzantine rite in Ukrainian language) parallel to the Latin hierarchy.

It depends from the Roman Congregation for the Oriental Churches.

Its episcopal see is the Cathedral of the Protection of the Mother of God in Olsztyn in the Warmian-Masurian Voivodeship.

It also has a Co-Cathedral, St. Bartholomew and Protection of the Mother of God, in Gdańsk, in the Pomeranian Voivodeship.

As per 2020, it pastorally served in 43 parishes with 26 priests (22 diocesan, 4 religious, that belong to the Order of Saint Basil the Great).