The Sheikh Lotfollah Mosque (Persian: مسجد شیخ لطف الله, romanized: Masjid-i Shaykh Lutfallah;) is a Shi'ite mosque, located on the eastern side of Naqsh-e Jahan Square, Isfahan, Isfahan province, Iran. Construction of the mosque started in AH 1011 (1602/1603 CE) and was finished in AH 1028 (1618/1619) and it is one of the masterpieces of Iranian architecture that was built during the Safavid era. It was designed by the chief architect Mohammad Reza Isfahani, during the reign of Shah Abbas the Great. On the advice of Arthur Upham Pope, Reza Shah Pahlavi had the mosque rebuilt and repaired in the 1920s.

The Sheikh Lotfollah Mosque, completed in the Safavid style, is one of the most important architectural projects built on Isfahan's maidan, prominent for its location, scale, design, and ornamentation. The mosque is registered, along with the Naghsh-e Jahan Square and other surrounding structures, as a UNESCO World Heritage Site; and was added to the Iran National Heritage List on 6 January 1932, administered by the Cultural Heritage, Handicrafts and Tourism Organization of Iran.