Caliph Mirza Masroor Ahmad - who represents tens of millions of Ahmadis across the world - led the assembled faithful of the minority sect in prayers at a farm near East Worldham in the north of the county.
The gathering, known as the Jalsa Salana, began on Friday with a sermon and the raising of the community's black-and-white flag alongside the Union Jack.
Concluding yesterday, the Caliph told some 30,000 adherents from more than 100 countries: "It is up to Muslims to stand up and reject all forms of extremism and terrorism.
"It is the task of Ahmadi Muslims to show the true teachings of Islam which are of peace love, mercy and compassion."
On Saturday, the Caliph awarded prizes to women for academic achievements and delivered a sermon on the rights of women.
The Ahmadiyya Muslim Community was established in 1889 in India and is led by a spiritual caliphate, with tens of millions of adherents.
Many Muslims consider them heretics, and they often suffer from persecution.