Zanzibar Revolutionary Day is celebrated every 12th of January to commemorate the day people of Zanzibar overthrew Sultanate administration. In 1963 Zanzibar Island had been granted independence from Britain . In July 1963 the Sultanate government held parliamentary elections which resulted in the Arab minority retaining power to an extent of making Zanzibar an overseas territory of Oman despite winning 54% of the votes.
That incident provoked the African majority. To solve the problem, the Afro Shirazi Party (ASP) allied with Umma Party to join force. On 12th January 1964 the ASP, lead by John Okello mobilized around 600 revolutionaries to Zanzibar town and overthrew the Sultanate government.