Sadaq Khān (Bengali: সাদক খান), also known as Mohammad Sadeq Khan (Bengali: মোহাম্মদ সাদেক খান, Persian: صادق خان), was a Faujdar of the Mughal Bengal's Sylhet Sarkar.
In 1678, Farhad Khan took a one year break from being the faujdar of Sylhet as he was appointed the task of being the faujdar of Chittagong.
It is said that Sadeq was ordered by Farhad to have built a mosque (which now remains incomplete) west of the former Sylhet Police lines.
An inscription on a certain mazar (mausoleum) in the dargah of Shah Jalal was found to have been built in 1689.
Syed Murtaza Ali is of the opinion that this is possibly the grave of Sadeq.