Gmina Byczyna is an urban-rural gmina (administrative district) in Kluczbork County, Opole Voivodeship, in south-western Poland. Its seat is the town of Byczyna, which lies approximately 15 kilometres (9 mi) north of Kluczbork and 54 km (34 mi) north of the regional capital Opole.
The gmina covers an area of 182.89 square kilometres (70.6 sq mi), and as of 2019 its total population is 9,305.