Sommerein is a town in the district of Bruck an der Leitha, in the Austrian state of Lower Austria. It lies in the eastern part of the country, within the federal province that surrounds Vienna.
Administratively, Sommerein belongs to the Bruck an der Leitha district, one of Lower Austria's political districts. The town is situated in the Leitha Hills area, a landscape of low wooded hills between the Vienna Basin and the Hungarian border.