In Islam, khums (Arabic: خُمْس Arabic pronunciation: [xums], literally 'one fifth') refers to the required religious obligation of any Muslims to pay one-fifth of their acquired wealth from certain sources toward specified causes. It is treated differently in Shia and Sunni Islam. This tax is paid to the imam, caliph or sultan, representing the state of Islam,[1][2] for distribution between the orphans, the needy, and the [stranded] traveler.[3]

In Sunni Islam tradition, the scope of khums tax has been ghanim, which is defined as the spoils of war. In Shia Islam tradition, states Abdulaziz Sachedina, the scope of khums tax has included, (1) booty (al-ghanima), (2) objects obtained from the sea (al-ghaws), (3) treasure (al-kanz), (4) mineral resources (al-ma'adin), (5) gainful earnings (arbaah al-makaasib, business profits), (6) the lawful (al-halaal) which has become mixed up with the unlawful (al-haraam), and (7) land which is transferred from a Muslim to a dhimmi (a free non-Muslim who is adheres to the law and is protected by the fact he resides in that Islamic State) by the latter's purchase of it.[2][4] The recipients of the collected khums have been the descendants of Muhammad and the Islamic clergy.[5][6]

Khums is a 20% tax that must be paid on all items regarded as ghanima (Arabic: الْغَنيمَة, booty seized with war). There are differing legal traditions within Islam about what constitutes ghanima, and thus how far-reaching khums should be. In some jurisdictions, khums included a 20% tax paid on minerals extracted in regions under the control of the state. Khums is different and separate from other Islamic taxes such as zakat and jizya.[1][7]