William Terence Kirby (born January 2, 1973), popularly known as Dr. Will, is an aesthetic dermatologist, an associate clinical professor of dermatology, and a reality television personality. He is known for winning the CBS reality show Big Brother 2 as well as winning The Price Is Right and appearing on multiple medical television programs as an aesthetic dermatology expert. He is often considered as one of the best Big Brother players of all time.

Kirby's father is the American poet, David Kirby. In 2011, Kirby became engaged to Erin Brodie, who was a two-time winner of the reality series For Love or Money. They were married in 2017. Kirby and Brodie have two children.