Syedna Hebatullah-il-Muʾayyad Fiddeen bin Syedna Ibrahim Wajihuddin (Died: 1st Shaban 1193 AH (13 August 1779 AD)) was the 40th Dā'ī al-Mutlaq of the Dawoodi Bohra sect.

[1] He succeeded his father, the 39th Dā'ī al-Mutlaq, Syedna Ibrahim Wajihuddin to the religious post.

[2] His period of Da'wat was from then until his death at the age of 68 (1780 AD (1200 AH)).

During his tenure, a group of dissidents called Hebtiyas emerged led by Ismail bin Abdur-Rasool and supported by Ismail's son Hebatullah.

Muʾayyad Fiddeen's deputies were: Syedna Abduttayyeb Zakiuddin succeeded Syedna Hebatullah-il-Muʾayyad Fiddeen as the 41st Da'i al-Mutlaq in 1780 AD (1200 AH).