Haardt Castle, Heritage villa in Neustadt an der Weinstraße, Germany.

Haardt Castle is a schloss-like villa built from 1876 for August Ritter von Clemm on the northeastern edge of the medieval Winzingen Castle site above the Haardt district of Neustadt an der Weinstraße. Architect Franz Huber's design was completed in 1893 with a circular pavilion and a large terrace. The building stands at 231 metres on the southeastern spur of the Schlossberg.

The villa was commissioned in 1876 after August Ritter von Clemm purchased the property a year earlier and sought to build a modern residence. This construction occurred during a period when wealthy business owners in the region were reshaping their properties and influencing local architecture.

The name Haardter Schloss suggests a castle, but locals also call it Haardter Schlössel, a diminutive referring to its dainty size, or Villa Clemm after its builder. Since 2002 part of the building has housed the Gute Aussichten exhibition forum for photography, which visitors can look for alongside the residential rooms.

Part of the estate is generally open to the public, but the owner reserves the right to close it when needed. The hillside position gives a wide view over the Rhine plain. The main building holds flats and the Gute Aussichten photography exhibition forum, so visits concern the grounds rather than the interiors.

A 2002 renovation revealed original 19th-century wallpaper hidden beneath wall coverings, offering insights into the villa's original interior design. These discoveries preserved authentic decorative choices made by residents and demonstrated how rooms were embellished during that era.