Masjid e Tooba or Tooba Mosque (Urdu: مسجد طوبٰی) is in Karachi, Sindh, Pakistan, and is locally known as the Gol Masjid.
Masjid e Tooba was built in 1969 in Defence Housing Society Karachi, Karachi. It is just off main Korangi Road. Masjid e Tooba is often claimed to be the largest single-dome mosque in the world. It is also major tourist attraction in Karachi. Masjid e Tooba is built with pure white marble. The dome is 72 meters (236 feet) in diameter and is balanced on a low surrounding wall with no central pillars. Masjid e Tooba has a single minaret standing 70 meters high. The mosque is the 18th largest in the world with the central prayer hall having a capacity of 5,000 people.
It was built keeping acoustics in mind. A person speaking inside one end of the dome can be heard at the other end. This mosque was designed by Pakistani architect Dr Babar Hamid Chauhan and the engineer was Zaheer Haider Naqvi.