Knock First is an American reality television series in which an adolescent is chosen for a total room makeover by the Knock First crew. The first series aired starting in the fall of 2003 on ABC Family.

The premise of the show was to shape the room in which the teenager lives into a space that represents them better. Teenagers who had been living in the same room since they were toddlers are able to redesign the room according to their desires.

The series included four designers: Taniya Nayak, John Gidding, Kathy Kuo, Shane Booth, and two carpenters: Carrie Roy, Andy Hampton.

The first season of Knock First centered mainly around teenagers in and around the Northeast, whereas the second season expanded to homes in California, to a slightly older audience.

The show theme for the first two seasons was titled " I Am", and was written and produced by Widelife, also creators of the theme for Bravo's Queer Eye For The Straight Guy, and performed by Faith Trent.

The show was redesigned for its third season and now places more responsibility for the completion of the project on the recipient.