Burgruine Senftenberg, Medieval castle ruins in Senftenberg, Austria.

Burgruine Senftenberg is the ruin of a hilltop castle on a hill in the market town of Senftenberg in Lower Austria's Krems district. Three gateways, the square keep, a shield wall and a tower remain; the tower's base is rectangular, its middle oval and its upper quarter hexagonal.

The castle was first mentioned in written records in 1197 with Ruedeger de Senftenberc as the owner. Over the following centuries, it changed hands multiple times under Austrian rulers.

The castle gave its name to the Senftenberg lineage, first recorded on 26 April 1197 when Rudegerus de Senftenberc appears as a witness in a charter. The ruin is a protected monument, and the Senftenberg castle-ruin association holds it on a 100-year lease and works on its restoration.

The ruin is open all year and a continuous road leads up to a small car park right by the site, so the climb can be shortened. The Senftenberg castle-ruin association holds a 100-year lease and has taken on its renovation. Sturdy shoes are still useful on the uneven ground.

Around 1520, robbers regularly stayed inside the castle, as records document. The castle was taken and destroyed in 1645 by Swedish troops under General Torstenson during the Thirty Years' War, after which it fell into decay.