Syedna Abdullah Badruddin bin Syedna AbdulHusain Husamuddin (Arabic: عبدُالله بَدرُالدين); born 11 July 1846) was an Indian-born religious leader, and the 50th Da'i al-Mutlaq of the Dawoodi Bohra sect. He was the son of Syedna AbdulHusain Husamuddin, whose family lineage can be traced back to Syedi Fakhruddin Shaheed. When the 49th Da'i al-Mutlaq Syedna Mohammed Burhanuddin did nass upon him, all those people who used to say, "After Syedna Mohammed Burhanuddin, the sect would come to an end", could not believe their eyes.