Károly observation tower in Sopron, Observation tower on Károly Hill, Sopron, Hungary.

Károly observation tower is a 23-metre tower of rough-hewn stone on the 398-metre Károly-magaslat hilltop above Sopron, built to Oszkár Winkler's final plans and inaugurated on 12 June 1936. From its top level the view reaches the city, the Sopron mountains, and in clear weather Pozsony beyond the Fertő, the Ság to the east and the Schneeberg to the west.

Romwalter Károly, a Sopron printer and publisher, and his son had the first wooden lookout built here in 1876 (some sources say 1878). In 1902 the city beautifiers judged repairs too costly and planned a stone tower, but construction finished only in 1936 after the bank holding the donations went bankrupt. Oszkár Winkler designed the 23-metre tower, inaugurated on 12 June 1936.

The first floor holds the permanent exhibition called the Botanists' Sanctuary, opened in 1996. Its display cases and short texts present the work of Pál Kitaibel, Endre Gombocz and Zoltán Kárpáti, while paintings by Vera Csapody show plants named by Kitaibel and Ferenc Ádám Waldstein. A second exhibition, opened on 27 March 2002, covers Csapody, Gyula Roth and Oszkár Winkler.

Multiple hiking trails connect to the tower and allow access from different directions while supporting nature observation and photography activities. Sturdy footwear is helpful since the paths lead uphill.

Following renovations in the 1990s, a local civic organization took over management and established educational facilities at the site. This development turned it into a popular destination for school groups and nature enthusiasts.