Sheikh Lotfollah Mosque (Persian: مسجد شیخ لطف الله‎‎) is one of the architectural masterpieces of Safavid Iranian architecture, standing on the eastern side of Naghsh-i Jahan Square, Isfahan, Iran.

Construction of the mosque started in 1603 and was finished in 1619. It was built by the chief architect Shaykh Bahai, during the reign of Shah Abbas I of the Safavid dynasty.
Of the four monuments that dominated the perimeter of the Naqsh-e Jahan Square, this one was the first to be built.

The purpose of this mosque was for it to be a private mosque of the royal court, unlike the Masjed-e Shah, which was meant for the public. For this reason, the mosque does not have any minarets and is of a smaller size. Indeed, few Westerners at the time of the Safavids even paid any attention to this mosque, and they certainly did not have access to it. It wasn’t until centuries later, when the doors were opened to the public, that ordinary people could admire the effort that Shah Abbas had put into making this a sacred place for the ladies of his harem, and the exquisite tile- work, which is far superior to those covering the Shah Mosque.

To avoid having to walk across the maydān when getting to the mosque, Shah Abbas had the architect build a tunnel spanning across the piazza, from the Ali Qapu palace, to the mosque. When reaching the entrance of the mosque, one would have to walk through a passage that winds round and round, until one finally reaches the main building. Along this passage there were standing guards, and the obvious purpose of this design was for the women of the harem to be shielded as much as possible from anyone entering the building. At the main entrance of the mosque there were also standing guards, and the doors of the building were kept closed at all times. Today, these doors are open to visitors, and the passage traversing underneath the field is no longer in use.