The Biggest Loser: Families is the sixth season of the NBC reality television series The Biggest Loser. The sixth season premiered on September 16, 2008, featuring Alison Sweeney as the host and Bob Harper and Jillian Michaels as the contestants' trainers.

The cast was revealed on August 29, 2008. Eight duos began the challenge, adding up to a total of 16 contestants.

From Week 1 to Week 5, the Green, Red, Orange & Brown Teams trained with Bob, while the Purple, Gray, Yellow & Pink Teams trained with Jillian. In Week 5, these "Family Teams" were disbanded and the contestants were split into the Blue Team and the Black Team. In week 8, the teams were split again and the competition went into individuals. Amy Cremen was originally under Jillian's training, but in week 5, was placed in and eliminated under Bob's training. Phillip Parham started the competition under Bob's training but was eliminated under Jillian's training.

Michelle Aguilar was named the Biggest Loser on December 16, 2008, after losing 110 pounds. She won $250,000. Heba was named the Biggest Loser of the eliminated contestants, and won $100,000. However, if Heba were not eliminated during the finale by America's vote she would've become the Biggest Loser.