Äcem Mosque, known as Әҗем мәчете or Äcem mäçete in Tatar Cyrillic and Latin respectively (pronounced [æˈʑem]), and in Russian as Ази́мовская мече́ть (Azimovskaya mechet), is a prominent cathedral mosque situated in Kazan, Tatarstan, Russia. It is situated in the southern part of the Old Tatar Quarter, an area rich in history and predominantly inhabited by Tatars. The mosque stands as one of approximately a dozen historical mosques within the district.

The construction of the mosque was sponsored by a wealthy Tatar merchant, Mortaza Äcimev, hence the name. The construction started in 1887 and was completed in 1890. The architect is unknown. The architectural style isnational romance eclecticism. The mosque has a 51-meters height minaret near the door, two halls, it is one-storied. The interior is designed in the medieval Oriental traditions. In 1930 the mosque was closed done by the authorities. In 1990-1992 it underwent reconstruction of both facades and the interior. In 1992 it was returned to the believers.^[1]