This paper aims to present the structural design and the rehabilitation process as well as the site assessment of the reconstruction and rehabilitation of the twelfth-century Grand Al-Nouri Mosque in Al-Nouri Complex, which is a part of the project Revive the Spirit of Mosul in Iraq. UNESCO launched the project Revive the Spirit of Mosul in February 2018 in order to reconstruct the old city after the destruction and looting from the wars with ISIS (Daesh) in 2017. Al-Nouri Complex includes the Great Al-Nouri Mosque and the 45-m-high Al-Hadba Minaret, which are the iconic historic landmarks of the old city of Mosul on the western side of the Tigris River, and it was built by Nur Al-Din Zengi during the twelfth century. Al-Nouri Mosque was reconstructed in 1942 using the original 40 octagonal Moslawi marble columns, and alabaster arches, the mihrab brought from the Ummayad Mosque in Mosul dates back to 956 AD, masonry stones, and a reinforced concrete roof. In this paper, the structural performance of Al-Nouri Mosque has been investigated through site observations, experimental tests, and structural analyses. Due to the several destructive earthquakes recorded around Mosul, a 3D finite element model of the whole mosque using a commercial finite element program has been developed considering the actual material properties and the effect of wind and seismic actions. Generally, the output results of the structural analysis models showed that the obtained compressive stress values did not exceed the compressive strength values defined for the original footing stones and Moslawi marble. Also, the recommended rehabilitation methodology was proposed to enhance the structural characteristics of the dome, the original Moslawi marble columns, and the old stone footings under the marble columns.