Mailberg is a town in the district of Hollabrunn in Lower Austria, Austria. It lies in the Weinviertel region of the country, north of Vienna.
The town was first mentioned in records in 1055. Castle Mailberg has been owned and run by the Austrian Grand Priory of the Sovereign Military Order of Malta since 1146. It now serves as a castle hotel and as a Vinothek for the local Winemakers Community "Mailberg Valley".
Mailberg is known for its wine production.