The 25-year-old Scotland international is the Bulls' second major recruit, following the capture of Warrington's England prop Garreth Carvell, and will fill the gap created by the departure of Elliott Whitehead.
Ferguson, who is out of contract at Huddersfield at the end of the year, has played in the Giants' last 15 Super League matches after starting the season on loan to Hull KR, and scored two tries in an eye-catching performance against Bradford at the Magic Weekend in May.
Bulls coach Francis Cummins said: "After the developments with Elliott, I needed a back-rower and Dale was the man I wanted.
"He tends to go under the radar but he's consistent and has strike power as well, as he showed against us at the Magic Weekend.
"It's really pleasing that he's chosen us over other clubs, especially ones he is familiar with. He's heard about what is going on here and wants to be part of it."
Bradford chairman Omar Khan said: "Dale is an exciting signing for us.
"We faced opposition from several clubs for his signature but he was impressed with what Francis outlined to him and chose to come here."
- Sports & Recreation
- Garreth Carvell
- Francis Cummins