Khan’s Mosque, also known as Kasim Khan Mosque, is an 18th–19th century mosque featuring a 16th-century minaret, located in the city of Kasimov in the Ryazan region. It is a significant monument of medieval Tatar religious architecture. The mosque is a two-story structure with a dome in the classical style and a two-tiered minaret, shaped like a low cylinder beneath a pointed dome, resting on a sturdy base.

From the 1930s until 2013, the building was repurposed as a museum. Closer to the Oka River stands the tekie (tomb) of Shah Ali Khan.

According to legend, the mosque was originally constructed in the 15th century by Prince Kasim, the first ruler of the Kasimov Khanate. However, historical sources, such as the writings of Khan Uraz-Muhammad’s court chronicler, Kadir-Ali-bek, suggest it was built by Khan Shah-Ali in the mid-16th century. The only surviving element from this ancient structure is its stone minaret. The original brick mosque was demolished in 1702 by order of Peter I, who, according to legend, mistook it for a church while sailing along the Oka River and instinctively crossed himself before it.

In 1768, with the approval of Empress Catherine II, a new mosque was constructed on the old foundation near the preserved minaret, likely repurposed as a watchtower. The new structure, built by Bektemir-seid, his son Burkhan-seid Shakulov, Ibrahim-murza Chanyshev, and others, was a single-story stone building with a hipped board roof. An inscription on the mosque’s wall, along with an imperial decree, confirms this reconstruction.

Above the mosque’s entrance, a stone bears an inscription in Old Tatar. In 1835, the mosque was expanded with a second floor, built of brick, through the efforts of Burkhan Bektemirovich’s son, Salih Seid, and his grandson, Hamza Seid Shakulov.

From 1938, the mosque functioned as a local history museum. In November 2013, the Arbitration Court of the Ryazan Region ruled to transfer the mosque back to the Spiritual Administration of Muslims of the European Part of Russia.