The Zanzibar Revolution (Arabic: Thawrat Zanjibr) occurred in 1964 and led to the overthrow of the Sultan of Zanzibar and his mainly Arab government by local African revolutionaries. Zanzibar was an ethnically diverse state consisting of a number of islands off the east coast of Tanganyika, which had been granted independence by Britain in 1963. In a series of parliamentary elections preceding independence, the Arab minority succeeded in retaining the hold on power it had inherited from Zanzibar's former existence as an overseas territory of Oman. Frustrated by under-representation in Parliament despite winning 54 per cent of the vote in the July 1963 election, the African Afro-Shirazi Party (ASP) early in the morning of 12 January 1964, led by John Okello, the (ASP) youth leader of the Pemba branch, mobilised around 600800 revolutionaries on the main island of Unguja (Zanzibar Island) whom he had mobilized months earlier. Having overrun the country's police force and appropriated their weaponry, the insurgents proceeded to Zanzibar Town, where they overthrew the Sultan and his government. Reprisals against Arab and South Asian civilians on the island followed; the resulting death toll is disputed, with estimates ranging from several hundred to 20,000. The moderate ASP leader Abeid Karume became the country's new president and head of state.

The new government's apparent communist ties concerned Western governments. As Zanzibar lay within the British sphere of influence, the British government drew up a number of intervention plans. However, the feared communist government never materialised, and because British and American citizens were successfully evacuated, these plans were not put into effect. Meanwhile, the Communist Bloc powers of East Germany and the Soviet Union, along with the anti-Soviet People's Republic of China, established friendly relations with the new government by recognising the country and sending advisors. Karume succeeded in negotiating a merger of Zanzibar with Tanganyika to form the new nation of Tanzania, an act judged by contemporary media to be an attempt to prevent communist subversion of Zanzibar. The revolution ended 200 years of Arab dominance in Zanzibar, and is commemorated on the island each year with anniversary celebrations and a public holiday.

Zanzibar (; Swahili: Zanzibar; Arabic: زِنْجِبَار, romanized: Zinjibār) is an insular autonomous region of Tanzania. It is composed of the Zanzibar Archipelago in the Indian Ocean, 25–50 kilometres (16–31 mi) off the coast of the mainland, and consists of many small islands and two large ones: Unguja (the main island, referred to informally as Zanzibar) and Pemba Island. The capital is Zanzibar City, located on the island of Unguja. Its historic centre, Stone Town, is a World Heritage Site.

Zanzibar's main industries are spices, raffia and tourism. In particular, the islands produce cloves, nutmeg, cinnamon, and black pepper. For this reason, the Zanzibar Archipelago, together with Tanzania's Mafia Island, are sometimes referred to locally as the "Spice Islands". Tourism in Zanzibar is a more recent activity, driven by government promotion that caused an increase from 19,000 tourists in 1985, to 376,000 in 2016. The islands are accessible via 5 ports and the Abeid Amani Karume International Airport, which can serve up to 1.5 million passengers per year.Zanzibar's marine ecosystem is an important part of the economy for fishing and algaculture and contains important marine ecosystems that act as fish nurseries for Indian Ocean fish populations. Moreover, the land ecosystem is the home of the endemic Zanzibar red colobus, the Zanzibar servaline genet, and the extinct or rare Zanzibar leopard. Pressure from the tourist industry and fishing as well as larger threats such as sea level rise caused by climate change are creating increasing environmental concerns throughout the region.