Vikštejn Castle, Medieval castle ruin in Radkov, Czech Republic.

Vikštejn Castle is a ruin on a high rocky spur above the Moravice river near Radkov, in the Moravian-Silesian region of the Czech Republic. Its remains stand on the cliff edge above the village of Vítkov-Podhradí, and the site has been protected as a cultural monument since 1964.

The castle was built in the 13th century by a noble family as a stronghold to control the surrounding area. It changed hands several times over the following centuries before being abandoned and falling into ruin.

The name Vikštejn is a Czech rendering of the German Burg Wigstein, the form used in German sources. According to local tradition, the minnesinger Walther von der Vogelweide was a guest of the castle's founder, Vítek z Kravař.

The ruin is reached by marked hiking trails starting from the nearby villages, with information panels along the way. The ground is uneven and some walls are unstable, so sturdy footwear is strongly recommended.

The towers were placed so that defenders could watch several approaches at the same time, which required a precise reading of the surrounding terrain. Walking around the outside of the ruin makes it easy to see why this particular hill was chosen for the site.