The Kazasker Mosque is a mosque in the 19 Mayıs neighborhood of Kadıköy, Istanbul. It was built in 1902 by Kasidecizade Süleyman Sırrı Efendi, a kazasker of Sultan Abdulhamid II.^[1]

The mosque has a wooden minbar and preaching (vaiz) platform, a tiled mihrab, and a single minaret. The mosque courtyard includes a small cemetery with the graves of Süleyman Sırrı Efendi, his son Ahmet Talat Kasidecioğlu, and others.^[2]