The Mayor Synagogue, also known as the Majorka Synagogue,[1] is a former Jewish congregation and synagogue, located on Hasköy Avenue, in the Hasköy district of Beyoğlu, Istanbul, in the Istanbul Province of Turkey.

According to historian Lorans Tanatar Baruh, the synagogue was built in the Byzantine era and was called Mayor because it was the largest in the neighborhood.

[2] Another historian claims the synagogue was built 300 to 500 years ago by Jews from Majorca.

[2][3] The synagogue building is now used as storage space, workshops, and a billiard parlor.

In September 2009, artist Serge Spitzer chose this site for his installation Molecular Istanbul.