Mehmet Bey Mosque, Ottoman mosque in Serres, Greece.

Mehmet Bey Mosque is a religious structure featuring a central prayer hall topped by a large dome measuring about 14.5 meters in diameter. The building was constructed using yellow limestone and brick, and it is flanked by four smaller rooms with half-domes on the east and west sides, creating a symmetrical layout.

The structure was built in 1492 by Mehmet Bey, son-in-law of Sultan Bayezid II, representing Ottoman presence in northern Greece during the 15th century. Later, floods from the Agioi Anargyroi stream caused damage that led to the cessation of its religious function.

Locals call the building Hagia Sophia, after the church that once stood on the site. The mosque was built in 1492–1493 by Mehmet Bey, son-in-law of Sultan Bayezid II, in memory of his father Ahmed Pasha Kedin, executed in 1482. Near it stands the tomb of the family of Ismail Bey, built in 1814.

The site can be reached on foot and is located in an accessible area of Serres, making it easy for visitors to explore the building's exterior and surroundings. It is advisable to be aware that the structure is currently a protected archaeological site and to observe appropriate caution when visiting.

The mosque is locally called Hagia Sophia, a name it shares with the great Byzantine church of Constantinople. Ottoman chronicler Evliya Çelebi wrote that its gardens, planted with cypresses and visited by many birds, had no rival, and that the mosque's fame reached from Greece to Persia.