Bennett, 18, has put pen to paper on a loan deal that will keep him at the Coral Windows Stadium until January 2015.
He won't feature in this Tuesday evening's Capital One Cup tie at Morecambe but he should be registered in time for this weekend's trip to Walsall.
The highly promising forward, who can also easily operate as a winger, has joined the Bantams after recent interest from at least one other club in Sky Bet League 1.
Bennett, a product of Derby's academy, signed a new four-year deal with the Rams towards the end of last month having spent a period on loan last season in League 2 with Chesterfield.
Having made his Derby debut at the tender age of just 15 back in 2011 - becoming the youngest player in the club's history as a result - Bennett has made 32 appearances for the Rams in total so far, including a run-out against Chelsea in the F.A Cup last season.
Bennett has also played for England at under 16, under 17 and under 19 level. The England youth international was named the Championship's Scholar of the Year for last season.
Speaking about Bennett's signing, Bantams boss Phil Parkinson said: "We are delighted by Mason's arrival.
"I am sure he will be a great addition to the squad and we look forward to working with him over the coming months."