Gaj Wielki (Polish pronunciation: [ɡaj ˈvjɛlkʲi]) is a village in the administrative district of Gmina Kaźmierz, within Szamotuły County, Greater Poland Voivodeship, in west-central Poland. It lies approximately 6 kilometres (4 mi) south of Kaźmierz, 15 km (9 mi) south of Szamotuły, and 24 km (15 mi) west of the regional capital Poznań.