Copernicus Tower in Frombork, Medieval tower in Frombork, Poland

Copernicus Tower is a red-brick Gothic tower standing on Cathedral Hill in Frombork, Poland, once part of the town's defensive wall. It now belongs to the museum complex around Frombork Cathedral and holds an astronomy exhibition inside.

The tower was built in the Middle Ages as part of Frombork's town wall and originally served a defensive purpose. In the early 1500s, Nicolaus Copernicus used it as a place to carry out astronomical observations.

The tower's name comes from Nicolaus Copernicus, who owned it from 1504 to 1543; it has been called the Copernicus Tower since 1610. Since July 2023 its three floors hold the exhibition "The Private World of Nicolaus Copernicus", with a medieval kitchen, a bedroom and the scholar's study, where a figure of Copernicus sits at his table.

The tower is open daily from 9:30 to 12:30 and from 13:00 to 17:00 (2023). The exhibition occupies three levels inside the tower, with a medieval kitchen on the first, a bedroom on the second and Copernicus's study on the third. The tower stands in the north-west corner of Cathedral Hill.

The tower was first recorded in 1499 as a residential tower and belonged to Copernicus from 1504 to 1543; the name Copernicus Tower (Curia Copernicana) came into use only around 1610. Swedish troops damaged it in the war of 1626, and canon Eustachy Nenchen paid for its repair.