Gross Wohnsdorf Castle, Medieval castle in Kurortnoe, Russia.

Gross Wohnsdorf Castle is a ruined Teutonic Order castle above the Lava (Alle) River at Kurortnoye in the Kaliningrad region. Only the 1356 gate tower survives; the rest was dismantled after an 1830 fire, and its stones built the manor house erected in 1868/69 in the former bailey park.

The Teutonic Order built a wooden-and-earth castle here in the 13th century on the site of the Prussian stronghold Kapostete. Lithuanian troops destroyed it in 1319 and again in 1347, prompting a stone rebuild begun in 1356 and finished around 1372. From 1468 the Order pledged it to Hans von Weyer, and from 1688 it belonged to the von Schrötter family until 1945.

The castle gave its name to the village of Groß Wohnsdorf, renamed Kurortnoje in 1950 when it merged with Agnesenhof. The gate tower where Friedrich Leopold von Schrötter grew up hosted philosophical conversations between his family and Immanuel Kant, a frequent guest. Since 2007 the ruins have been a regional cultural heritage site.

The site is located in a rural area of Pravdinsky District and can be visited by those interested in medieval military architecture. Local authorities can provide information about the ruins and their historical background.

The gate tower that survives is the one rebuilt by architect Friedrich Gilly after the 1790 fire; the castle itself was quarried away after the 1830 blaze, and its stone went into the estate building put up in 1868/69 in the former outer bailey park.