Nikolaikirche, Medieval church ruins in Zerbst, Germany.

Nikolaikirche is a ruined Gothic hall church in Zerbst. Its surviving south tower is the only remnant of the 12th-century Romanesque granite basilica; the choir was completed in 1446 and the nave in 1486. The three stone spires added in 1533/34 were destroyed in 1945, and a viewing platform now stands where the central tower once was.

A Romanesque granite basilica was built in the 12th century, one of the first stone churches east of the Elbe. Around 1430 work began on a Gothic hall church, with the choir finished in 1446 and the nave in 1486. The three stone spires, added in 1533/34, were destroyed in the bombing of 16 April 1945; demolition was prevented and a support association founded in 1991.

The church's name comes from St. Nicholas, and it was the council church of Zerbst, where the Anhalt territorial church's first ordinations were held in 1578 under superintendent Wolfgang Amling. Since 1991 a support association has secured the ruin, which now hosts concerts and cultural events; the five bells in the north tower, including the Gloriosa, serve the neighbouring Trinitatiskirche.

The ruins are freely accessible from outside and can be visited during daylight hours, allowing views from different angles. It is wise to wear sturdy shoes since the ground can be uneven in places.

The north tower holds five bells, including the Gloriosa, the largest bell in Anhalt. The peal is rung for the neighbouring Trinitatiskirche, so the ruined church still sounds across Zerbst even though its own services ended in 1945.