Gerasdorf bei Wien is a town in the district of Korneuburg in the Austrian state of Lower Austria. The city has 10,862 inhabitants.

The city is located in the Weinviertel district of Lower Austria on the northern city boundary of Vienna. The area of the township covers 35.24 square kilometres, about one percent of the area is wooded.

It was the only municipality north of the Danube in Wien-Umgebung District until the district was dissolved in 2016.