The Masjid-i-Jahan Numa commonly known as Jama Masjid of Delhi, is the principal mosque of Old Delhi in India. Commissioned by the Mughal Emperor Shah Jahan, builder of the Taj Mahal, and completed in the year 1656 AD, it is one of the largest and best-known mosques in India. It is also at the beginning of a very busy and popular street/center in Old Delhi, Chandni Chowk.

The name Jama Masjid is a reference to the weekly congregation observed on Friday (the yaum al-jum`a) at the mosque. The courtyard of the mosque can hold up to twenty-five thousand worshippers. The mosque also houses several relics in a closet in the north gate, including a copy of the Qur'an written on deer skin.

The mosque was the result of the efforts of over 5,000 workers, over a period of six years

The courtyard of the mosque can be reached from the east, north and south by three flights of steps, all built of red sandstone. Prior to the 1857 War of Indian Independence, there was a madrassah near the southern side of the mosque, which was pulled down after the mutiny. The Lal Qila or the Red Fort stand towards the east of the mosque. The Jama Masjid combines the best of he Hindu and Islamic styles of architecture. It is said that the walls of the mosque were tilted at a certain angle so that at the time of an earthquake, the walls do not collapse in the courtyard but outwards.

Jama Masjid is cluttered by devotees who offer namaz, especially during Muslim Festivals. For those who don't belong to non - Muslim community, a specified time is mentioned to enter the mosque.