The diocese of Bac Ninh () is a Roman Catholic diocese of Vietnam.
The creation of the diocese in present form was declared November 24, 1960.
The diocese covers an area of 12,227 km<sup>2</sup>, and is a suffragan diocese of the Archdiocese of Hanoi.
By 2004, the diocese of Bac Ninh had about 123,090 believers (1.8% of the population), 23 priests and 47 parishes.
Queen of the Rosary Cathedral in Bac Ninh has been assigned as the Cathedral of the diocese.