Taher Saifuddin (سيدنا طاهر سيف الين, 4 August 1888 – 12 November 1965) was the 51st Da'i al-Mutlaq of the Dawoodi Bohras, a sect within Shia Islam. He was the son of the 49th Da'i al-Mutlaq Mohammed Burhanuddin, whose family lineage can be traced back to Syedi Fakhruddin Shaheed.