The İsabey Mosque (Turkish: İsabey Camii), constructed in 1374-1375, is one of the oldest and most impressive works of architectural art remaining from the Anatolian beyliks. The mosque is situated between the Saint Jean Church and the remains of the Temple of Artemis on the skirts of the Ayasluğ Hills at Selçuk, İzmir, formerly Ephesus in Turkey. It was built by the architect Şamlı Dımışklıoğlu Ali in honor of the Aydınoğlu İsa Bey. In the 19th century, it was also used as a caravanserai.
The mosque has two main entrances, to the east and to the west. The western wall has inscriptions and geometric shapes engraved. These walls are covered with marble, whereas the façades on the remaining sides are made of cut stone. It is built asymmetrically on a 48 m by 56 m (157 by 184 ft) base. The rims of its domes (of diameters of 9.4 m and 8.1 m) are decorated with İznik (Nicaea) tiles. 12 round columns stand inside its courtyard encircled with porches. Its brick minaret is built on an octagonal base, and the upper part from the balcony is ruined. The mosque had another minaret on the west, which is totally destroyed now. The mihrab (niche or altar) was moved to another mosque, due to a door opened there. There is an octagonal Seljuk türbe made of stone and bricks, with a pyramid shaped roof, right next to the mosque.