Klein-Neusiedl is a municipality in the district of Bruck an der Leitha, in the Austrian state of Lower Austria. It is located in the eastern part of the country, within the federal province of Lower Austria.
Administratively, Klein-Neusiedl falls under the Bruck an der Leitha district, one of the districts that make up Lower Austria. As a municipality, it forms a single local administrative unit within that district.